Method and system for evaluating deformation state of lithium iron phosphate rotary kiln
By collecting and analyzing data on roller pressure, cylinder temperature, and rotation angle, and using an inverse proportional exponential decay model to distinguish between thermal bending and plastic deformation, the problem of accuracy in assessing the deformation state of rotary kilns was solved, and the stability of the sealing effect and the long-term reliability of the equipment were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-08
- Publication Date
- 2026-03-27
AI Technical Summary
Existing technologies cannot effectively distinguish between thermal bending and plastic deformation in lithium iron phosphate rotary kilns, leading to sealing failure and affecting product quality.
By collecting data on roller pressure, cylinder temperature, and rotation angle, pressure fluctuations are corrected using an inverse proportional exponential decay model and a thermal distribution non-uniformity coefficient. The true plastic deformation index is calculated to distinguish between thermal bending and plastic deformation, and the sealing gap is compensated by an airtight device.
It enables accurate assessment of the deformation state of the rotary kiln, avoids misjudgment, ensures sealing effect, prevents gas leakage, and guarantees product quality and equipment life.
Smart Images
Figure CN121739734A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of industrial equipment monitoring and control, and in particular to a lithium iron phosphate rotary kiln deformation state evaluation method and system. BACKGROUND
[0002] As the mainstream positive electrode material of lithium ion batteries, the sintering process in the production process of lithium iron phosphate is crucial. The rotary kiln is the core equipment for sintering lithium iron phosphate, usually using electric heating method, through the rotation of the kiln body to drive the internal material to roll and heat. In actual production, the rotary kiln cylinder is supported by multiple support devices at the bottom, and there is a long suspended section between the support devices. In order to prevent external air from entering the oxidized material or internal exhaust gas from leaking, the kiln head and kiln tail usually adopt a high-precision sealing structure combining mechanical sealing and gas sealing.
[0003] In the long-term operation process, the rotary kiln faces complex deformation problems. On the one hand, due to the large span, high self-weight and high temperature environment of the rotary kiln, the cylinder of the suspended section is prone to permanent downward bending, i.e. plastic deformation, under the action of gravity and high temperature creep. On the other hand, if the power fluctuation of the electric heating element or the uneven distribution of the material occurs, it will cause uneven temperature distribution in the circumferential direction of the cylinder, resulting in thermal bending, i.e. elastic deformation. Both of these two deformations will cause the kiln body to be eccentric when rotating, affecting the sealing effect.
[0004] The existing technology usually uses laser displacement sensors or single monitoring of the fluctuation of the supporting roller pressure to judge the deformation of the rotary kiln. However, the existing technology is limited in that it cannot distinguish between thermal bending and plastic deformation. Thermal bending is usually temporary and can be restored as the temperature is uniform; while plastic deformation is a permanent damage to the equipment. If thermal bending is misjudged as plastic deformation for mechanical adjustment, it will damage the equipment; on the contrary, if the real plastic deformation is ignored, it will cause the deviation of the coaxiality of the kiln head and kiln tail to increase, damage the sealing gap, cause the gas seal to fail, and seriously affect the product quality of lithium iron phosphate. SUMMARY
[0005] The present application provides a lithium iron phosphate rotary kiln deformation state evaluation method and system to solve the problem of misjudgment and sealing failure caused by the inability to distinguish between thermal bending and plastic deformation in the existing technology.
[0006] In a first aspect, the lithium iron phosphate rotary kiln deformation state evaluation method of the present application comprises the following steps: Collecting the supporting roller pressure data, the cylinder circumferential surface temperature data and the rotation angle data during the operation of the rotary kiln, setting the time for one rotation of the rotary kiln as a sampling period, and spatially aligning the supporting roller pressure data and the cylinder circumferential surface temperature data based on the rotation angle in each sampling period to obtain a pressure sequence set and a circumferential temperature sequence set; The pressure fluctuation intensity index, which characterizes the pressure dispersion and extreme value characteristics within the current cycle, is calculated based on the pressure sequence set; the heat distribution non-uniformity coefficient, which characterizes the temperature dispersion in the circumferential direction, is calculated based on the circumferential temperature sequence set. Using an inverse proportional exponential decay model that includes a heat-sensitive adjustment factor, the pressure fluctuation intensity index is nonlinearly corrected based on the heat distribution non-uniformity coefficient. The true plastic deformation index after stripping away the thermal effect interference is calculated. The true plastic deformation index is used to characterize the degree of permanent deformation of the rotary kiln shell. The actual plastic deformation index is compared with the preset deformation alarm threshold. If the actual plastic deformation index is less than the deformation alarm threshold, the rotary kiln is determined to be in normal condition. If the actual plastic deformation index is greater than or equal to the deformation alarm threshold, the rotary kiln cylinder is determined to have undergone plastic deformation, triggering an alarm and generating a control command based on the actual plastic deformation index to adjust the air supply pressure of the rotary kiln gas sealing device to compensate for the sealing gap.
[0007] Its beneficial effects are as follows: This invention combines pressure fluctuation characteristics with heat distribution characteristics, and uses the heat distribution non-uniformity coefficient to correct pressure fluctuations, effectively distinguishing between thermal bending caused by temperature non-uniformity and plastic deformation caused by structural problems, avoiding false alarms caused by thermal effect interference, and ensuring the accuracy of deformation assessment.
[0008] Preferably, the pressure fluctuation intensity index is calculated using the following formula: ; in, As an indicator of the intensity of pressure fluctuations, The rated bearing pressure of the roller hydraulic system. The total number of pressure sampling points within the pressure sequence set; The first in the set of pressure sequences Pressure values at each pressure sampling point; The arithmetic mean of the pressure values at all pressure sampling points within the pressure sequence set; The maximum value of the roller pressure data within the pressure sequence set; It is the minimum value of the roller pressure data within the pressure sequence set.
[0009] Its beneficial effects are that it not only statistically analyzes the overall dispersion of pressure, but also amplifies the abnormal fluctuation characteristics, making the calculated pressure fluctuation intensity index more sensitive to the eccentric extrusion effect of the rotary kiln.
[0010] Preferably, the heat distribution non-uniformity coefficient is calculated using the following formula: ; in, The coefficient for non-uniform heat distribution is denoted as . It is a natural constant. The standard process temperature is set for the rotary kiln. The first in the set of circumferential temperature sequences Temperature values at each temperature measurement point; It is the arithmetic mean of the temperature values at all temperature measurement points in the circumferential temperature sequence set; This represents the total number of temperature measurement points in the circumferential temperature sequence set.
[0011] Its beneficial effect is that it can effectively measure whether there is local overheating or undercooling in the circumferential direction, providing an assessment basis for subsequent judgment on whether pressure fluctuations are caused by thermal effects.
[0012] Preferably, the true plastic deformation index is calculated using the following formula: ; in, The true plastic deformation index. As a heat-sensitive regulator, As an indicator of the intensity of pressure fluctuations, is the coefficient for uneven heat distribution.
[0013] Its beneficial effects are: it can significantly reduce the weight of pressure fluctuation index when the temperature distribution is extremely uneven, thereby achieving noise reduction of thermal interference and ensuring that the obtained true plastic deformation index reflects the physical health of the equipment.
[0014] Preferably, the step of generating control commands based on the true plastic deformation index and adjusting the air supply pressure of the rotary kiln gas sealing device to compensate for the sealing gap includes: Based on the extent to which the actual plastic deformation index exceeds the deformation alarm threshold, the required boost pressure value for the air seal device is calculated, and the actuator is controlled to increase the air supply pressure to enhance the air seal damping.
[0015] Its beneficial effects are: the deformation assessment results can be directly used to guide the pressure compensation of the gas sealing system, realizing the transformation from passive monitoring to active control, effectively preventing gas leakage caused by deformation, and ensuring the atmosphere stability of the lithium iron phosphate sintering process.
[0016] Preferably, the roller pressure data is collected by a high-frequency pressure sensor installed at the hydraulic station of the supporting roller.
[0017] Preferably, the temperature data of the circumferential surface of the cylinder is collected by an infrared thermometer.
[0018] Preferably, the infrared temperature scanner is arranged on the outside of the cylinder.
[0019] Preferably, the rotation angle data is acquired by a rotary encoder installed at the motor end.
[0020] In a second aspect, the lithium iron phosphate rotary kiln deformation state evaluation system of the present application comprises a memory and a processor, the memory stores computer instructions, and the processor executes the computer instructions to implement the lithium iron phosphate rotary kiln deformation state evaluation method described above.
[0021] The present application introduces a temperature non-uniformity coefficient based on information entropy logic, and dynamically corrects the pressure fluctuation characteristics through an exponential decay model, so that the system can effectively distinguish between thermal bending and plastic deformation, and can still prevent false positives in the case of severe temperature field fluctuations in the rotary kiln. The technical problem of low detection accuracy in high temperature working conditions in the prior art is solved. The present application can automatically adjust the air seal damping and compensate for the sealing gap when detecting real plastic deformation by linking the evaluation results with the air seal control system, effectively preventing the influence of gas leakage on product quality and prolonging the service life of the mechanical seal. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 The flowchart of the lithium iron phosphate rotary kiln deformation state evaluation method provided by the embodiment of the present application is shown.
[0023] Figure 2 The rotary kiln running state multi-source data monitoring graph in the embodiment of the present application is shown.
[0024] Figure 3 The comparison graph of the evaluation effect of the embodiment of the present application and the prior art is shown. DETAILED DESCRIPTION
[0025] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.
[0026] As Figure 1 shown, the embodiment of the lithium iron phosphate rotary kiln deformation state evaluation method provided by the present application comprises the following steps: S1, collect the riding wheel pressure data, the cylinder circumferential surface temperature data and the rotation angle data in the rotary kiln running process, set the time of one rotation of the rotary kiln as a sampling period, and spatially align the riding wheel pressure data and the cylinder circumferential surface temperature data based on the rotation angle in each sampling period to obtain a pressure sequence set and a circumferential temperature sequence set.
[0027] Specifically, high-frequency pressure sensors are installed at each supporting roller hydraulic station of the rotary kiln to collect roller pressure data in real time. Meanwhile, infrared temperature scanning instruments are arranged along the axial direction outside the rotary kiln cylinder to scan and obtain the temperature data of the circumferential surface of the cylinder. In addition, the rotation angle data of the rotary kiln are obtained through the rotary encoder installed at the motor end. Since the collection frequencies of the sensors may be different, the rotation angle is used as the reference for alignment.
[0028] In each sampling period, the roller pressure data and the circumferential surface temperature data of the cylinder are mapped to the corresponding angle positions. Assuming that the pressure sequence set is , where is the total number of pressure sampling points in the pressure sequence set, and assuming , each degree in 360 degrees corresponds to a pressure sampling point. Assuming that the circumferential temperature sequence set is , where is the total number of temperature sampling points in the circumferential temperature sequence set, and assuming , each 10 degrees corresponds to a temperature sampling point. As shown in Figure 2 , the real-time pressure data and the circumferential temperature distribution in a sampling period are shown. In this way, through the collection of multi-source data and the spatial alignment based on the rotation angle, the time deviation between different sensors is eliminated, and accurate corresponding data basis is provided for subsequent analysis.
[0029] S2, calculate the pressure fluctuation intensity index representing the pressure dispersion degree and the extreme value characteristics in the current period based on the pressure sequence set, and calculate the thermal distribution uneven coefficient representing the temperature dispersion degree in the circumferential direction based on the circumferential temperature sequence set.
[0030] The bending of the rotary kiln causes the cylinder to be in an eccentric state when rotating, thereby causing periodic pressure fluctuations on the roller. Specifically, the pressure fluctuation intensity index is calculated by the following formula: ; , where is the pressure fluctuation intensity index; is the rated bearing pressure of the roller hydraulic system, which is a fixed constant; is the total number of pressure sampling points in the pressure sequence set; is the pressure value of the th pressure sampling point in the pressure sequence set; is the arithmetic mean of the pressure values of all pressure sampling points in the pressure sequence set; is the maximum value of the roller pressure data in the pressure sequence set; is the minimum value of the roller pressure data in the pressure sequence set.
[0031] For example, suppose five pressure sampling points are collected within a certain sampling period, forming a pressure sequence set. This pressure sequence set... It is 10 MPa. It is 10.2 MPa. It is 9.8 MPa, assuming The pressure is 20 MPa. Substituting these data into the formula for calculating the pressure fluctuation intensity index, we get... It is 0.129 MPa.
[0032] Specifically, the coefficient of thermal non-uniformity is calculated using the following formula: ; in, The coefficient for non-uniform heat distribution is denoted as . It is a natural constant. The standard process temperature is set for the rotary kiln. The first in the set of circumferential temperature sequences Temperature values at each temperature measurement point; It is the arithmetic mean of the temperature values at all temperature measurement points in the circumferential temperature sequence set; This represents the total number of temperature measurement points in the circumferential temperature sequence set.
[0033] For example, suppose , , Calculate the heat distribution non-uniformity coefficient for cases A and B respectively. Case A: Temperature is uniform, and the temperature values at all measurement points in the circumferential temperature sequence set are uniform. Calculations yielded The value is 1. Case B: Uneven temperature distribution, with localized overheating, resulting in... for Calculations yielded The value is 1.169. This indicates that the more uneven the temperature distribution, the greater the coefficient of thermal non-uniformity.
[0034] Thus, by constructing two indices—pressure fluctuation intensity index and thermal distribution non-uniformity coefficient—the pressure fluctuation amplitude at the mechanical level and the temperature dispersion at the thermodynamic level were quantified, providing key characteristic parameters for subsequent coupled analysis.
[0035] S3. Using an inverse proportional exponential decay model that includes a heat-sensitive adjustment factor, the pressure fluctuation intensity index is nonlinearly corrected based on the heat distribution non-uniformity coefficient. The true plastic deformation index after stripping away the thermal effect interference is calculated. The true plastic deformation index is used to characterize the degree of permanent deformation of the rotary kiln shell.
[0036] Specifically, the true plastic deformation index is calculated using the following formula: ; wherein, is a true plastic deformation index, is a thermal sensitivity adjustment factor, is a pressure fluctuation intensity index, is a thermal distribution unevenness coefficient.
[0037] Exemplarily, the thermal sensitivity adjustment factor is used to control the punishment degree of temperature unevenness, assuming is 1.5. The example data after step S2 are calculated: for case A, is 1, is 1.5, is 0.129 MPa, these data are substituted into the true plastic deformation index calculation formula, and is 0.129 MPa. This indicates that in the case of temperature uniformity, the monitored pressure fluctuation is completely identified as true plastic deformation. For case B, assuming that the pressure fluctuation also increases due to thermal bending at this time, is 0.5 MPa, and is 2.5, is 1.5. These data are substituted into the true plastic deformation index calculation formula, and is 0.026 MPa.
[0038] As can be seen, although the monitored pressure fluctuation intensity index in case B is as high as 0.5 MPa, due to the detection of a large thermal distribution unevenness coefficient, after the model correction, the evaluated true plastic deformation index is greatly reduced, only 0.026 MPa, effectively eliminating the interference caused by thermal bending, and avoiding the misjudgment of thermal interference as serious plastic deformation. In this way, by performing nonlinear correction, the thermal effect caused by the fluctuation component is effectively suppressed while the plastic deformation characteristics are retained, so that the true physical health degree of the rotary kiln can be accurately evaluated.
[0039] S4, comparing the true plastic deformation index with a preset deformation alarm threshold value, if the true plastic deformation index is less than the deformation alarm threshold value, determining that the rotary kiln is normal; if the true plastic deformation index is greater than or equal to the deformation alarm threshold value, determining that the rotary kiln cylinder has plastic deformation, triggering an alarm and generating a control instruction according to the true plastic deformation index to adjust the gas supply pressure of the rotary kiln gas seal device to compensate for the sealing gap.
[0040] Specifically, the deformation alarm threshold value is preset as 0.4 MPa, if the calculated , determining that the rotary kiln is normal, maintaining the current operating parameters. If the calculated , determining that the rotary kiln cylinder has plastic deformation, the system immediately triggers an alarm, and generates a control instruction according to The magnitude exceeding the deformation alarm threshold, the required pressure increase of the gas seal device is calculated. wherein is a proportional coefficient. Then, the control actuator increases the supply pressure to increase the gas seal damping, preventing gas leakage caused by the increase of the seal gap due to the deformation of the cylinder.
[0041] As Figure 3 shown, the effect comparison of the present application and the prior art is shown. The left column group simulates the working condition one disturbed by only thermal effect, in which the evaluation value of the prior art is high, resulting in false alarm, while the evaluation value of the present application is low, determining normal. The right column group simulates the real structure settlement working condition two, and the present application can accurately identify the fault. In this way, by applying the evaluation result to active control, not only the timely early warning of the fault is realized, but also the continuous and stable operation of the rotary kiln under slight deformation is ensured through the automatic compensation mechanism, avoiding the product quality accidents caused by seal failure.
[0042] The implementation principle of the lithium iron phosphate rotary kiln deformation state evaluation method of the embodiment of the present application is that the present application constructs a temperature non-uniformity coefficient based on information entropy logic, and uses an exponential decay model to dynamically correct the pressure fluctuation characteristics, which can effectively distinguish between thermal bending and plastic deformation, prevent false alarms even in the case of severe fluctuations in the temperature field of the rotary kiln, and solve the problem of low detection accuracy of the prior art under high temperature working conditions. In addition, the present application establishes a linkage mechanism between the evaluation result and the gas seal control system, which can automatically adjust the gas seal damping to compensate for the seal gap when real plastic deformation is detected, thereby effectively preventing the influence of gas leakage on product quality and significantly prolonging the service life of the mechanical seal.
[0043] The embodiment of the lithium iron phosphate rotary kiln deformation state evaluation system provided by the present application includes a memory and a processor, and the memory stores computer instructions. When the processor executes the computer instructions, the lithium iron phosphate rotary kiln deformation state evaluation method in the above embodiment is realized.
[0044] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.
Claims
1. A method for evaluating the deformation state of a lithium iron phosphate rotary kiln, characterized in that, Includes the following steps: Data on roller pressure, cylinder circumferential surface temperature, and rotation angle are collected during the operation of the rotary kiln. The time for one rotation of the rotary kiln is set as a sampling period. Within each sampling period, the roller pressure data and cylinder circumferential surface temperature data are spatially aligned based on the rotation angle to obtain a pressure sequence set and a circumferential temperature sequence set. The pressure fluctuation intensity index, which characterizes the pressure dispersion and extreme value characteristics within the current cycle, is calculated based on the pressure sequence set; the heat distribution non-uniformity coefficient, which characterizes the temperature dispersion in the circumferential direction, is calculated based on the circumferential temperature sequence set. Using an inverse proportional exponential decay model that includes a heat-sensitive adjustment factor, the pressure fluctuation intensity index is nonlinearly corrected based on the heat distribution non-uniformity coefficient. The true plastic deformation index after stripping away the thermal effect interference is calculated. The true plastic deformation index is used to characterize the degree of permanent deformation of the rotary kiln shell. The actual plastic deformation index is compared with the preset deformation alarm threshold. If the actual plastic deformation index is less than the deformation alarm threshold, the rotary kiln is determined to be in normal condition. If the actual plastic deformation index is greater than or equal to the deformation alarm threshold, the rotary kiln cylinder is determined to have undergone plastic deformation, triggering an alarm and generating a control command based on the actual plastic deformation index to adjust the air supply pressure of the rotary kiln gas sealing device to compensate for the sealing gap.
2. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The pressure fluctuation intensity index is calculated using the following formula: ； in, As an indicator of the intensity of pressure fluctuations, The rated bearing pressure of the roller hydraulic system. The total number of pressure sampling points within the pressure sequence set; The first in the set of pressure sequences Pressure values at each pressure sampling point; The arithmetic mean of the pressure values at all pressure sampling points within the pressure sequence set; The maximum value of the roller pressure data within the pressure sequence set; It is the minimum value of the roller pressure data within the pressure sequence set.
3. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The coefficient of heat distribution non-uniformity is calculated using the following formula: ； in, The coefficient for non-uniform heat distribution is denoted as . It is a natural constant. The standard process temperature is set for the rotary kiln. The first in the set of circumferential temperature sequences Temperature values at each temperature measurement point; It is the arithmetic mean of the temperature values at all temperature measurement points in the circumferential temperature sequence set; This represents the total number of temperature measurement points in the circumferential temperature sequence set.
4. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The true plastic deformation index is calculated using the following formula: ； in, The true plastic deformation index. As a heat-sensitive regulator, As an indicator of the intensity of pressure fluctuations, is the coefficient for uneven heat distribution.
5. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The step of generating control commands based on the true plastic deformation index to adjust the air supply pressure of the rotary kiln gas sealing device to compensate for the sealing gap includes: Based on the extent to which the actual plastic deformation index exceeds the deformation alarm threshold, the required boost pressure value for the air seal device is calculated, and the actuator is controlled to increase the air supply pressure to enhance the air seal damping.
6. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The roller pressure data is collected by a high-frequency pressure sensor installed at the hydraulic station supporting the roller.
7. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The temperature data of the circumferential surface of the cylinder is collected by an infrared thermometer.
8. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 7, characterized in that, The infrared temperature scanner is located on the outside of the cylinder.
9. The method for evaluating the deformation state of a lithium iron phosphate rotary kiln according to claim 1, characterized in that, The rotation angle data is collected by a rotary encoder installed at the motor end.
10. A deformation state assessment system for a lithium iron phosphate rotary kiln, characterized in that, It includes a memory and a processor. The memory stores computer instructions. When the processor executes the computer instructions, it implements the method for evaluating the deformation state of a lithium iron phosphate rotary kiln as described in any one of claims 1-9.