An energy efficiency data monitoring optimization method for a sintering intake electric preheating system

Abstract

The present application relates to sintering air intake technical field, specifically to a kind of sintering air intake electric preheating system energy efficiency data monitoring optimization method;According to harmonic distortion rate, three-phase unbalance degree and power factor, obtain electric energy quality characteristic value;According to electric energy quality characteristic value and input power, obtain initial energy efficiency;According to the discrete characteristics of gas pressure in different positions in preheating section, obtain airflow uniformity characteristic value;According to the gas flow of preheating section, gas density, hot air temperature of inlet and outlet and preset material reference temperature, obtain heat transfer efficiency characteristic value.The present application corrects initial energy efficiency according to airflow uniformity characteristic value and heat transfer efficiency characteristic value, obtains final energy efficiency;According to final energy efficiency, sintering air intake preheating is regulated;The energy efficiency monitoring accuracy of sintering air intake electric preheating system is improved.

Description

Technical Field

[0001] This invention relates to the field of sintering gas inlet technology, and more specifically to a method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system. Background Technology

[0002] In the current field of energy efficiency monitoring for sintering processes, the evaluation method for inlet gas electric preheating systems typically employs a real-time thermal power calculation method based on the first law of thermodynamics. This method involves deploying temperature, pressure, and flow sensors at the inlet and outlet of the preheater to collect gas operating parameters in real time, and then calculating the effective thermal power obtained by the gas according to classical thermodynamic formulas, thereby assessing the energy efficiency level of the preheating system. The advantage of this technology lies in its clear physical meaning and simple, efficient calculation. In a sintering inlet gas electric preheating system under pure electric preheating, it can quantify the heat increment of the gas at the inlet and outlet of the preheater, providing operators with an intuitive energy efficiency reference indicator.

[0003] While existing thermodynamic-based methods for monitoring thermal power can effectively assess the energy output level of a preheating system under stable sintering conditions, good equipment status, and pure electric preheating, these methods have significant limitations in the more energy-efficient dynamic operating environment of gas recycling. Firstly, the inlet gas of the preheater is not entirely cold air, but a mixture of other gases, including recovered hot air from the cooling section. Its composition and temperature change dynamically, making it impossible for traditional thermodynamic formulas to accurately calculate the true effective electrical power. Secondly, these formulas assume that all the heat gained by the gas is effectively absorbed by the sintering material, ignoring heat loss due to poor airflow organization, material accumulation, or delayed control response. This results in the calculated gas thermal power failing to accurately reflect the actual contribution of the preheating system to the sintering process. Ultimately, this leads to low accuracy in monitoring the energy efficiency of the sintering gas inlet electric preheating system. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for monitoring and optimizing energy efficiency data in a sintering gas inlet electric preheating system. The specific technical solution adopted is as follows:

[0005] Obtain the input power, harmonic distortion rate, three-phase imbalance, power factor, gas flow rate, gas density, gas pressure at different locations, and hot air temperature at the inlet and outlet of the preheater power supply circuit.

[0006] The power quality characteristic value is obtained based on the harmonic distortion rate, the three-phase imbalance, and the power factor; the initial energy efficiency is obtained based on the power quality characteristic value and the input power.

[0007] The uniformity characteristic value of airflow is obtained based on the discrete characteristics of gas pressure at different locations within the preheating section; the heat transfer efficiency characteristic value is obtained based on the gas flow rate, gas density, inlet and outlet hot air temperature, and preset material reference temperature within the preheating section.

[0008] The initial energy efficiency is corrected based on the airflow uniformity characteristic value and the heat transfer efficiency characteristic value to obtain the final energy efficiency; the sintering inlet preheating is regulated based on the final energy efficiency.

[0009] Further, the step of obtaining power quality characteristic values ​​based on the harmonic distortion rate, the three-phase imbalance, and the power factor includes:

[0010] In the formula, R represents the power quality characteristic value, F represents the power factor, k represents the preset equipment characteristic coefficient, and T represents the harmonic distortion rate. This indicates the degree of three-phase imbalance.

[0011] Further, the step of obtaining the initial energy efficiency based on the power quality characteristic value and the input power includes:

[0012] Calculate the product of the power quality characteristic value and the input power to obtain a first value; calculate the ratio of the first value to the input power to obtain the initial energy efficiency.

[0013] Furthermore, the step of obtaining the uniformity characteristic value of the airflow based on the discrete characteristics of the gas pressure at different locations within the preheating section includes:

[0014] In the formula, G represents the uniform characteristic value of airflow, and V represents the coefficient of variation of gas pressure.

[0015] Furthermore, the step of obtaining the heat transfer efficiency characteristic value based on the gas flow rate, gas density, inlet and outlet hot air temperature, and preset material reference temperature of the preheating section includes:

[0016] In the formula, W represents the characteristic value of heat transfer efficiency, and Q represents the gas flow rate. represents gas density, c represents gas specific heat capacity, H represents inlet hot air temperature, Y represents outlet hot air temperature, and M represents preset material reference temperature.

[0017] Further, the step of correcting the initial energy efficiency based on the airflow uniformity characteristic value and the heat transfer efficiency characteristic value to obtain the final energy efficiency includes:

[0018] The final energy efficiency is obtained by multiplying the initial energy efficiency, the airflow uniformity characteristic value, and the heat transfer efficiency characteristic value.

[0019] The present invention has the following beneficial effects:

[0020] In this invention, power quality characteristic values ​​are obtained based on harmonic distortion rate, three-phase imbalance, and power factor, reflecting the power quality-related losses during the conversion of electrical energy to heat energy. Initial energy efficiency is obtained based on the power quality characteristic values ​​and input power, determining energy waste and efficiency levels during energy conversion. Airflow uniformity characteristic values ​​are obtained based on the discrete characteristics of gas pressure at different locations within the preheating section, characterizing the pressure differences and determining whether different areas of the material are sufficiently heated. Heat transfer efficiency characteristic values ​​are obtained based on gas flow rate, gas density, inlet and outlet hot air temperatures, and a preset material reference temperature within the preheating section, analyzing the utilization of hot air heat during material heating and reflecting heat transfer efficiency. Finally, the initial energy efficiency is corrected based on the airflow uniformity characteristic values ​​and heat transfer efficiency characteristic values ​​to obtain the final energy efficiency; compared to existing methods that analyze preheating energy efficiency based on gas thermal power, this method improves the accuracy of energy efficiency monitoring. Attached Figure Description

[0021] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The flowchart illustrates an energy efficiency data monitoring and optimization method for a sintering gas inlet electric preheating system, as provided in one embodiment of the present invention. Detailed Implementation

[0023] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] The following description, in conjunction with the accompanying drawings, details the specific scheme of the energy efficiency data monitoring and optimization method for a sintering gas inlet electric preheating system provided by the present invention.

[0026] Please see Figure 1 The diagram illustrates a flowchart of an energy efficiency data monitoring and optimization method for a sintering gas inlet electric preheating system according to an embodiment of the present invention. The method includes the following steps:

[0027] Step S1: Obtain the input power, harmonic distortion rate, three-phase imbalance, power factor, gas flow rate, gas density, gas pressure at different locations, and hot air temperature at the inlet and outlet of the preheater power supply circuit.

[0028] In this embodiment of the invention, the implementation scenario is to monitor the energy efficiency of the sintering gas inlet electric preheating system and improve the accuracy of energy efficiency monitoring. A power quality analysis module is deployed in the preheater power supply circuit to collect the input power, harmonic distortion rate, and three-phase imbalance of the preheater power supply circuit. Temperature, pressure, and flow sensors are installed in the preheating section to collect gas flow rate, gas density, gas pressure at different locations, and inlet and outlet hot air temperatures. Statistical methods, such as the Raida criterion, are used to identify and eliminate abnormal data points caused by sensor drift or communication terminals, ensuring data validity. A moving average algorithm is used to smooth the instantaneous fluctuations of inlet and outlet hot air temperatures, gas flow rates, and other signals, improving data stability. It should be noted that the data collection frequency for each dimension is consistent, and the implementer can determine it according to the implementation scenario. The preprocessed data is normalized to eliminate the influence of magnitude and dimensions on subsequent calculations.

[0029] Step S2: Obtain power quality characteristic values ​​based on harmonic distortion rate, three-phase imbalance, and power factor; obtain initial energy efficiency based on power quality characteristic values ​​and input power.

[0030] To address the limitations of traditional thermal power monitoring methods, which can only calculate the heat of the gas exiting the preheater but cannot reflect the efficiency of electrical input and the effectiveness of heat transfer, this invention proposes a two-layer correction method for energy efficiency calculation. First, based on the power quality parameters of the preheater's power supply circuit, the electrothermal conversion efficiency characteristics are analyzed. Energy waste caused by conversion is removed from the input power to obtain the true electrical output power of the preheater, thus yielding the initial energy efficiency. Next, the measured harmonic distortion rate and three-phase imbalance are nonlinearly coupled to comprehensively reflect the superimposed degradation effect when harmonics and imbalance coexist. Then, the power factor is introduced as an independent correction term to reflect the influence of reactive power proportion. Therefore, power quality characteristic values ​​are obtained based on the harmonic distortion rate, three-phase imbalance, and power factor. Preferably, in this embodiment, the steps for obtaining power quality characteristic values ​​include:

[0031]

[0032] In the formula, R represents the power quality characteristic value, F represents the power factor, k represents the preset equipment characteristic coefficient, and T represents the harmonic distortion rate. This indicates the three-phase imbalance. It is a coupled effect term of harmonic distortion rate and three-phase unbalance. When both harmonics and current are normal, T and The value of this term is 0, indicating that harmonics and three-phase currents do not waste electrical energy. When the harmonic distortion rate and three-phase imbalance increase, this term increases, indicating increased energy loss. The harmonic formula is... In the formula This is the effective value of the fundamental current. It is the effective value of the h-th harmonic current, and then it is obtained through the formula for the effective value of the total current. The derivation yields ,and then Characterizes the current amplification factor caused by harmonics. Three-phase unbalance is a relative deviation; that is, the essence of three-phase unbalance is the degree to which the effective value of the current is amplified relative to the balanced state. This represents the current amplification factor caused by imbalance; the two factors act independently, and their multiplication gives the total amplification factor. The preset equipment characteristic coefficient k characterizes the sensitivity of the equipment to power quality degradation, ranging from 0 to 1. A larger value indicates a more significant energy loss caused by harmonic distortion rate and three-phase imbalance. Different degrees of harmonic distortion rate and three-phase imbalance can be experimentally calibrated, and the actual decrease in electrothermal conversion efficiency can be measured to fit and obtain the preset equipment characteristic coefficient. In this embodiment, it is taken as 0.2, but the implementer can determine it according to the implementation scenario. The power factor independently affects power; a larger value indicates lower losses. Therefore, a larger power quality characteristic value means a smaller overall impact of power quality on electrothermal conversion efficiency, higher power utilization, and higher energy efficiency.

[0033] Furthermore, the initial energy efficiency can be obtained based on the power quality characteristic value and the input power, specifically including: calculating the product of the power quality characteristic value and the input power to obtain a first value; calculating the ratio of the first value to the input power to obtain the initial energy efficiency; the closer the initial energy efficiency is to 1, the higher the electrothermal conversion efficiency.

[0034] Step S3: Obtain the airflow uniformity characteristic value based on the discrete characteristics of gas pressure at different locations in the preheating section; obtain the heat transfer efficiency characteristic value based on the gas flow rate, gas density, inlet and outlet hot air temperature, and preset material reference temperature in the preheating section.

[0035] While the initial energy efficiency characterizes the conversion of electrical energy into heat energy, it still cannot accurately characterize the proportion of heat effectively absorbed by the sintering material. Therefore, it is necessary to further correct the initial energy efficiency using the heat transfer state parameters monitored in the preheating section. Furthermore, the gas-solid heat transfer efficiency can be calculated based on the ratio of the actual temperature rise of the material to the theoretical expected temperature rise; a higher efficiency means a higher degree of heat absorption by the material and better heat transfer efficiency. Simultaneously, the uniformity of airflow distribution within the preheating section is analyzed, as the task of the preheating section is to uniformly heat the material; a more uniform gas distribution indicates a more comprehensive heat conduction effect. First, the airflow uniformity characteristic value is obtained based on the discrete characteristics of gas pressure at different locations within the preheating section. Preferably, in this embodiment of the invention, the step of obtaining the airflow uniformity characteristic value includes: In the formula, G represents the airflow uniformity characteristic value, and V represents the coefficient of variation of gas pressure. A larger coefficient of variation means a greater difference in gas pressure at different locations within the preheating section, resulting in a more uneven airflow distribution. Even with a larger average heat transfer, uneven airflow distribution can easily lead to insufficient heating of some areas of the material, reducing the total heat actually absorbed by the material. Therefore, a smaller airflow uniformity characteristic value means less uniform heating of the material and lower heat transfer efficiency. Furthermore, the heat transfer efficiency characteristic value can be obtained based on the gas flow rate, gas density, inlet and outlet hot air temperatures, and a preset material reference temperature in the preheating section. Preferably, in this embodiment of the invention, the step of obtaining the heat transfer efficiency characteristic value includes:

[0036]

[0037] In the formula, W represents the characteristic value of heat transfer efficiency, and Q represents the gas flow rate. The numerator represents the gas density, c represents the gas specific heat capacity, H represents the inlet hot air temperature, Y represents the outlet hot air temperature, and M represents the preset material reference temperature. The numerator represents the actual thermal power of the hot air in the preheating section. Because the preheating section only uses high-temperature gas to uniformly heat the material, ignoring the heat dissipation from the furnace wall, the temperature difference between the temperature entering and leaving the preheating section is entirely used for material heating. The preset material reference temperature refers to the lowest temperature that the hot air can reach under ideal heat transfer conditions. For example, if the material needs to be uniformly heated to 200 degrees Celsius in the preheating section, the preset material reference temperature is 200 degrees Celsius or slightly higher to maintain the heat transfer driving force; the implementer can determine this according to the implementation scenario. The denominator represents the theoretical maximum thermal power of the hot air in the preheating section. Assuming that the hot air transfers all its energy to the material, at which point the material and hot air temperatures are equal, and then it leaves the preheating section; therefore, the theoretical outlet hot air temperature of the preheating section is the required temperature for material heating in industrial applications, i.e., the preset material reference temperature. In reality, hot air cannot completely cool down to the material temperature and needs to maintain a certain temperature difference to drive heat transfer. Therefore, this ratio is usually less than 1. This ratio reflects the proportion of heat released by the hot air to the theoretical maximum heat that can be released under the current heat transfer conditions. In other words, the larger the characteristic value of heat transfer efficiency, the more fully the heat of the hot air is utilized, the better the heat transfer effect, and the higher the energy efficiency.

[0038] Step S4: Correct the initial energy efficiency based on the airflow uniformity characteristic value and heat transfer efficiency characteristic value to obtain the final energy efficiency; regulate the sintering inlet preheating based on the final energy efficiency.

[0039] After obtaining the airflow uniformity characteristic value and heat transfer efficiency characteristic value, the initial energy efficiency can be corrected based on these values ​​to obtain the final energy efficiency. Preferably, in this embodiment of the invention, the step of obtaining the final energy efficiency includes: calculating the product of the initial energy efficiency, the airflow uniformity characteristic value, and the heat transfer efficiency characteristic value to obtain the final energy efficiency. The larger the airflow uniformity characteristic value and the heat transfer efficiency characteristic value, the better the hot air heat transfer efficiency in the preheating section, the higher the utilization rate of thermal energy, and thus the greater the final energy efficiency. Conversely, the smaller the airflow uniformity characteristic value and the heat transfer efficiency characteristic value, the lower the utilization rate of thermal energy in the preheating section, and the lower the final energy efficiency. The final energy efficiency reflects the proportion of the electrical energy input to the preheating system that is converted into effective heat absorbed by the materials. The higher the final energy efficiency, the better the energy utilization rate of the preheating system; the lower the final energy efficiency, the lower the energy utilization rate of the preheating system, and the more necessary it is to regulate and optimize the preheating state.

[0040] Then, the preheating of the sintering inlet gas is regulated based on the final energy efficiency. When the final energy efficiency is lower than a preset energy efficiency threshold, regulation is implemented, for example, the preset energy efficiency threshold is 80%, which the implementer can determine according to the implementation scenario. The deviation between the final energy efficiency and the preset energy efficiency threshold is calculated. Based on this deviation and a preset control algorithm, such as PID control, fuzzy logic, or model predictive control, the adjustment amount of the preheater electric heating power, fan speed, or valve opening is dynamically calculated. The decision command is sent to the preheater power supply circuit and air volume regulation device to correct the operating parameters of the preheating system in real time and continuously monitor the changes in the final energy efficiency, forming a closed-loop feedback control until the energy efficiency returns to the target range. It should be noted that this regulation step is existing technology, and the specific process will not be elaborated further. Thus, by calculating the final energy efficiency, the accuracy of energy efficiency monitoring for the electric preheating of the sintering inlet gas is improved.

[0041] In summary, this invention provides a method for monitoring and optimizing the energy efficiency data of a sintering gas inlet electric preheating system. It obtains power quality characteristic values ​​based on harmonic distortion rate, three-phase imbalance, and power factor; obtains initial energy efficiency based on the power quality characteristic values ​​and input power; obtains airflow uniformity characteristic values ​​based on the discrete characteristics of gas pressure at different locations within the preheating section; and obtains heat transfer efficiency characteristic values ​​based on gas flow rate, gas density, inlet and outlet hot air temperatures, and a preset material reference temperature within the preheating section. This invention corrects the initial energy efficiency based on the airflow uniformity characteristic values ​​and heat transfer efficiency characteristic values ​​to obtain the final energy efficiency; it then regulates the sintering gas inlet preheating based on the final energy efficiency, thereby improving the accuracy of energy efficiency monitoring for the sintering gas inlet electric preheating system.

[0042] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0043] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system, characterized in that, The method includes the following steps: Obtain the input power, harmonic distortion rate, three-phase imbalance, power factor, gas flow rate, gas density, gas pressure at different locations, and hot air temperature at the inlet and outlet of the preheater power supply circuit. The power quality characteristic value is obtained based on the harmonic distortion rate, the three-phase imbalance, and the power factor; the initial energy efficiency is obtained based on the power quality characteristic value and the input power. The uniformity characteristic value of airflow is obtained based on the discrete characteristics of gas pressure at different locations within the preheating section; the heat transfer efficiency characteristic value is obtained based on the gas flow rate, gas density, inlet and outlet hot air temperature, and preset material reference temperature within the preheating section. The initial energy efficiency is corrected based on the airflow uniformity characteristic value and the heat transfer efficiency characteristic value to obtain the final energy efficiency; the sintering inlet preheating is regulated based on the final energy efficiency.

2. The method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system according to claim 1, characterized in that, The step of obtaining power quality characteristic values ​​based on the harmonic distortion rate, the three-phase unbalance, and the power factor includes: In the formula, R represents the power quality characteristic value, F represents the power factor, k represents the preset equipment characteristic coefficient, and T represents the harmonic distortion rate. This indicates the degree of three-phase imbalance.

3. The method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system according to claim 1, characterized in that, The step of obtaining the initial energy efficiency based on the power quality characteristic value and the input power includes: Calculate the product of the power quality characteristic value and the input power to obtain a first value; calculate the ratio of the first value to the input power to obtain the initial energy efficiency.

4. The method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system according to claim 1, characterized in that, The step of obtaining the uniformity characteristic value of the airflow based on the discrete characteristics of the gas pressure at different locations within the preheating section includes: In the formula, G represents the uniform characteristic value of airflow, and V represents the coefficient of variation of gas pressure.

5. The method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system according to claim 1, characterized in that, The step of obtaining the heat transfer efficiency characteristic value based on the gas flow rate, gas density, inlet and outlet hot air temperature, and preset material reference temperature of the preheating section includes: In the formula, W represents the characteristic value of heat transfer efficiency, and Q represents the gas flow rate. represents gas density, c represents gas specific heat capacity, H represents inlet hot air temperature, Y represents outlet hot air temperature, and M represents preset material reference temperature.

6. The method for monitoring and optimizing energy efficiency data of a sintering gas inlet electric preheating system according to claim 1, characterized in that, The step of correcting the initial energy efficiency based on the airflow uniformity characteristic value and the heat transfer efficiency characteristic value to obtain the final energy efficiency includes: The final energy efficiency is obtained by multiplying the initial energy efficiency, the airflow uniformity characteristic value, and the heat transfer efficiency characteristic value.

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