Temperature control method and system for composite defluorination agent calcination activation process

Abstract

The present application relates to the technical fields of industrial process monitoring and automatic temperature control, and discloses a temperature control method and system for a composite fluorine removal agent calcination activation process, which comprises the following steps: obtaining the running speed of equipment, the feeding flow rate, the gas phase and shell temperature, and the exhaust smoke moisture content; inversing the actual temperature of the material bed layer according to the radial heat transfer relationship; calculating the heat absorption disturbance heat according to the feeding flow rate and the exhaust smoke moisture content change rate; calculating the lead time constant according to the running speed, and distributing the heat absorption disturbance heat to the downstream predicted heating area in advance to calculate the feedforward compensation amount; inputting the deviation between the actual temperature and the target value into a prediction control model to solve the feedback adjustment amount, superimposing the feedforward and feedback adjustment amounts to generate a heat supply driving signal and outputting the heat supply driving signal to a heat supply adjustment mechanism; the present application eliminates the observation lag of the gas phase temperature measurement on the bed layer, realizes the cross-zone feedforward hedging of phase change heat absorption, suppresses the temperature overshoot, and prevents the fluorine removal agent channel from collapsing and sintering inactivation.

Description

Technical Field

[0001] This invention relates to a temperature control method and system for the calcination and activation process of a composite defluorinating agent, belonging to the field of industrial process monitoring and automatic temperature control technology. Background Technology

[0002] Rotary kilns are commonly used production equipment for heat treatment and activation of porous adsorption materials. The composite defluorinating agent undergoes preheating and dehydration, dehydroxylation activation, and crystal phase stabilization stages in the kiln. The temperature of each temperature zone needs to be stably maintained within the set process range. When the activation temperature is lower than the lower limit of the target range, the hydroxyl groups on the material surface are not sufficiently removed, which will reduce the adsorption capacity. When the local temperature exceeds the upper limit of the target range, the metal oxide matrix is ​​prone to sintering due to overheating, which will lead to the collapse of mesoporous channels and loss of activity.

[0003] In continuous production, the heat transfer process within a rotary kiln exhibits significant nonlinearity and is also influenced by the endothermic phase change of the material. This poses challenges to the monitoring and control of the material temperature. Existing temperature control systems typically utilize gas phase temperature sensors to collect the gas phase temperature within the kiln, comparing the measured temperature with a set value, and then adjusting the burner's heating load based on the temperature deviation. However, the material continuously tumbles within the inclined rotary kiln, and the thick material layer itself presents heat transfer resistance. Changes in the gas phase temperature cannot promptly reflect the true temperature of the material particle bed, resulting in a significant response delay in the temperature measurement signal. Furthermore, the evaporation of structural water and the hydroxyl condensation processes in the material are accompanied by strong endothermic reactions. When the feed moisture content or feed rate fluctuates, the endothermic flux of the phase change also becomes unstable. Changes, even abrupt changes, are possible. For example, Chinese invention patent CN116151022B discloses a real-time temperature estimation method for cement rotary kilns based on heat balance calculation. This method constructs a zero-dimensional heat balance model by treating the kiln body as a whole to achieve temperature estimation. However, the roasting and activation of the composite defluorinating agent along the kiln body axis exhibits significant phased evolution of physical properties and endothermic transfer characteristics of phase change. This type of zero-dimensional mechanism model highly lumps the parameters inside the kiln, ignoring the spatial distribution of the axial temperature gradient and the axial migration law of endothermic disturbances as the material rolls. It cannot accurately decouple the actual heating state of each axial micro-element inside the thick material layer, nor can it provide advanced feedforward power allocation to the downstream predicted temperature zone. When faced with fluctuations in the feed moisture content, it is still difficult to avoid the defects of axial local overburning or under-temperature deactivation.

[0004] Therefore, existing control methods essentially adjust the reaction and heat transfer processes of materials that change continuously with the movement of the kiln body based on the temperature deviation of local temperature measurement points. This makes it difficult to simultaneously handle large heat transfer lags and strong phase change endothermic disturbances, and also makes it difficult to ensure the consistency of activation effects of different batches of defluorinating agents. The technical problem to be solved by this invention is how to obtain the true temperature distribution of the material bed based on the operating status of the rotary kiln, and estimate the endothermic disturbances in advance by combining the enthalpy of the dehydration phase change reaction, and perform feedforward compensation in the heating control to reduce the impact of heat transfer lags and suppress temperature overshoot and fluctuations in the temperature zone. Summary of the Invention

[0005] To address the problems in the background art, the technical solution of the present invention is as follows: A temperature control method for the calcination and activation process of a composite defluorinating agent, comprising the following steps: Step S101: Obtain the operating speed, feed mass flow rate, axially distributed gas phase temperature data, flue gas moisture content, and equipment shell temperature data of the roasting equipment. Step S102: Based on the radial heat transfer relationship between the equipment shell, the gas phase and the material bed, calculate the dynamic angle of repose and heat exchange area of ​​the material in combination with the operating speed, and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and the equipment shell temperature data. Step S103: Based on the rate of change of feed mass flow rate and flue gas moisture content over time, and combined with the enthalpy of dehydration phase change reaction, calculate the dynamic endothermic disturbance heat of the current activation reaction zone. Step S104: Calculate the advance time constant that characterizes the axial migration rate of the material based on the operating speed, establish a feedforward spatial mapping relationship based on the collection location of the gas phase temperature data, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the advance time constant, and calculate the feedforward power compensation amount corresponding to each heating zone. Step S105: Input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve for the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate the heating drive signal, and output the heating drive signal to the heating regulation mechanism corresponding to each heating zone.

[0006] Preferably, step S102 includes the following sub-steps: Step S1021, calculating the inner wall temperature data of the equipment lining based on the equipment shell temperature data, ambient temperature, and thermal conductivity of the equipment lining; Step S1022, constructing a radial node heat balance equation based on the convective and radiative heat transfer from the gas phase to the material bed surface and the contact heat transfer from the inner wall of the equipment lining to the material bed; Step S1023, dynamically correcting the gas-material heat exchange area and the wall material heat exchange area by combining the dynamic packing angle of the material, and decoupling the calculation to obtain the actual temperature data of the material bed along the axial direction corresponding to each temperature measurement node.

[0007] Preferably, step S104 includes the following sub-steps: Step S1041, calculating the axial propulsion linear velocity of the material particles during the tumbling process based on the operating speed, the tilt angle of the roasting equipment, and the inner diameter of the equipment; Step S1042, multiplying the axial propulsion linear velocity by the preset response delay time of the heating adjustment mechanism to obtain the spatial displacement advance, and determining the mapping weight based on the projection span of the spatial displacement advance in the axially divided grid; Step S1043, projecting the dynamic heat absorption disturbance heat calculated in the upstream heating zone to the data input node of the downstream adjacent predicted heating zone according to the mapping weight.

[0008] Preferably, the calculation of the feedforward power compensation amount corresponding to each heating zone in step S104 includes the following sub-steps: Step S1044, inputting the dynamic heat absorption disturbance heat into the axial one-dimensional unsteady heat transfer energy balance equation, combined with the feed mass flow rate, the average specific heat capacity of the composite defluorinating agent, the target heating rate, and the convective heat loss from the equipment surface to the external environment; Step S1045, reversibly calculating the basic thermal power compensation value required to offset the heat absorption of the material dehydration phase change and the convective heat loss of the equipment, as the feedforward power compensation amount.

[0009] Preferably, in step S105, the process of solving the dynamic feedback adjustment amount is as follows: within the rolling optimization time domain, the combined optimization objective is to minimize the sum of squares of the tracking error of the actual temperature data of the material bed and the minimum change amplitude of the control increment. The opening change rate and opening extreme value of the gas regulating valve in the heating regulation mechanism are used as boundary constraints. The dynamic feedback adjustment increment corresponding to each heating zone in each control cycle is solved as the dynamic feedback adjustment amount.

[0010] Preferably, the heating regulation mechanism includes a gas regulating valve and a combustion-supporting fan, and the heating drive signal includes a gas regulating valve drive signal and a combustion-supporting fan frequency conversion drive signal. A dynamic timing decoupling logic is set between the gas regulating valve drive signal and the combustion-supporting fan frequency conversion drive signal. When the total heating power command increases by a step, the combustion-supporting fan frequency conversion drive signal is controlled to lead the output of the gas regulating valve drive signal. When the total heating power command decreases by a step, the gas regulating valve drive signal is controlled to lead the output of the combustion-supporting fan frequency conversion drive signal, thereby maintaining the preset micro-positive pressure and oxidizing atmosphere in the furnace.

[0011] Preferably, it also includes: when the feed mass flow rate is detected to drop to or below the preset safety lower limit threshold, forcibly clearing the dynamic heat absorption disturbance heat and cutting off the feedforward spatial mapping relationship; switching the heating control mode of each heating zone to a constant temperature waiting mode based solely on the equipment insulation reference heat load, and stopping the issuance of heating drive signals superimposed with feedforward power compensation.

[0012] Preferably, the method further includes: calculating an axial thermal crosstalk correction term based on the gas phase temperature gradient between adjacent heating zones in the calcination equipment and the material flow direction; and superimposing the axial thermal crosstalk correction term when calculating the feedforward power compensation to eliminate the axial multi-temperature zone thermal dynamic coupling effect caused by countercurrent heat transfer.

[0013] Preferably, it further includes: during a continuous temperature control cycle, acquiring the residual value between the equipment shell temperature data collected by the infrared thermal imaging temperature measurement device and the theoretical equipment shell temperature data calculated based on the radial heat transfer correlation; when the residual value continuously exceeds the preset allowable deviation range, triggering an adaptive update of the equivalent thermal conductivity parameter of the equipment lining in the radial heat transfer correlation, and recalculating the actual temperature data based on the updated equivalent thermal conductivity parameter.

[0014] A temperature control system for the calcination and activation process of a composite defluorinating agent, comprising a method for controlling the temperature during the calcination and activation process of the composite defluorinating agent, including: The data acquisition module is used to acquire data on the operating speed of the roasting equipment, the feed mass flow rate, the axially distributed gas phase temperature, the exhaust moisture content, and the equipment shell temperature. The temperature inversion calculation module is used to calculate the dynamic angle of repose and heat exchange area of ​​the material based on the radial heat transfer relationship between the equipment shell, the gas phase and the material bed, combined with the operating speed, and to invert and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and the equipment shell temperature data. The heat absorption disturbance calculation module is used to calculate the dynamic heat absorption disturbance of the current activation reaction zone based on the rate of change of feed mass flow rate and flue gas moisture content over time, combined with the enthalpy of dehydration phase change reaction. The feedforward spatial mapping module is used to calculate the advance time constant characterizing the axial migration rate of the material based on the operating speed, establish the feedforward spatial mapping relationship based on the acquisition location of the gas phase temperature data, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the advance time constant, and calculate the feedforward power compensation amount corresponding to each heating zone. The feedback optimization and drive module is used to input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve for the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate the heating drive signal, and output the heating drive signal to the heating regulation mechanism corresponding to each heating zone.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the temperature control of a composite defluorinating agent roasting and activation process, by simultaneously utilizing information such as the equipment shell temperature, gas phase temperature, and operating speed to determine the actual temperature of the material bed, the response lag and measurement deviation caused by relying solely on gas phase temperature measurement can be reduced. This allows the control system to more timely and accurately grasp the actual thermal state of the material in each axial temperature zone. As a result, the heating regulation of each heating zone is no longer based solely on changes in gas phase temperature, but can be based on the actual temperature of the material bed, which is beneficial to improving the accuracy of temperature monitoring and heating regulation during the roasting process.

[0016] 2. By determining the dynamic heat absorption disturbance generated during the material dehydration process based on the changes in feed mass flow rate and exhaust moisture content, and by performing feedforward power compensation in advance, the required heat can be replenished in time before the significant temperature drop caused by changes in heat absorption load. This can reduce the compensation delay caused by heat transfer lag in conventional feedback control, reduce temperature fluctuations caused by changes in feed moisture and dehydroxylation reaction, and make the heating response during the material activation process more timely.

[0017] 3. By using the feedforward power compensation amount in conjunction with the dynamic feedback adjustment amount obtained based on the actual temperature deviation of the material bed, the remaining temperature deviation can be further corrected while compensating for heat absorption disturbances in advance. This reduces temperature fluctuations and local overshoot caused by the thermal inertia of the rotary kiln and the mutual influence of multiple temperature zones. As a result, the material bed temperature can be kept more stably within the set activation temperature range, reducing local overburning caused by excessive heating and lowering the risk of mesoporous channel collapse and high-temperature crystalline phase deactivation. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the synergistic control of temperature inversion and feedforward feedback in the calcination material of the composite defluorinating agent of this invention. Figure 2 This is a diagram showing the functional modules and parameter interactions of the roasting and activation temperature control system of the present invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A method for temperature control during the calcination and activation process of a composite defluorinating agent includes the following steps: Step S101: Obtain the operating speed, feed mass flow rate, axially distributed gas phase temperature data, flue gas moisture content, and equipment shell temperature data of the roasting equipment. Step S102: Based on the radial heat transfer relationship between the equipment shell, the gas phase and the material bed, calculate the dynamic angle of repose and heat exchange area of ​​the material in combination with the operating speed, and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and the equipment shell temperature data. Step S103: Based on the rate of change of feed mass flow rate and flue gas moisture content over time, and combined with the enthalpy of dehydration phase change reaction, calculate the dynamic endothermic disturbance heat of the current activation reaction zone. Step S104: Calculate the advance time constant that characterizes the axial migration rate of the material based on the operating speed, establish a feedforward spatial mapping relationship based on the collection location of the gas phase temperature data, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the advance time constant, and calculate the feedforward power compensation amount corresponding to each heating zone. Step S105: Input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve for the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate the heating drive signal, and output the heating drive signal to the heating regulation mechanism corresponding to each heating zone.

[0022] Preferably, step S102 includes the following sub-steps: Step S1021, calculating the inner wall temperature data of the equipment lining based on the equipment shell temperature data, ambient temperature, and thermal conductivity of the equipment lining; Step S1022, constructing a radial node heat balance equation based on the convective and radiative heat transfer from the gas phase to the material bed surface and the contact heat transfer from the inner wall of the equipment lining to the material bed; Step S1023, dynamically correcting the gas-material heat exchange area and the wall material heat exchange area by combining the dynamic packing angle of the material, and decoupling the calculation to obtain the actual temperature data of the material bed along the axial direction corresponding to each temperature measurement node.

[0023] Preferably, step S104 includes the following sub-steps: Step S1041, calculating the axial propulsion linear velocity of the material particles during the tumbling process based on the operating speed, the tilt angle of the roasting equipment, and the inner diameter of the equipment; Step S1042, multiplying the axial propulsion linear velocity by the preset response delay time of the heating adjustment mechanism to obtain the spatial displacement advance, and determining the mapping weight based on the projection span of the spatial displacement advance in the axially divided grid; Step S1043, projecting the dynamic heat absorption disturbance heat calculated in the upstream heating zone to the data input node of the downstream adjacent predicted heating zone according to the mapping weight.

[0024] Preferably, the calculation of the feedforward power compensation amount corresponding to each heating zone in step S104 includes the following sub-steps: Step S1044, inputting the dynamic heat absorption disturbance heat into the axial one-dimensional unsteady heat transfer energy balance equation, combined with the feed mass flow rate, the average specific heat capacity of the composite defluorinating agent, the target heating rate, and the convective heat loss from the equipment surface to the external environment; Step S1045, reversibly calculating the basic thermal power compensation value required to offset the heat absorption of the material dehydration phase change and the convective heat loss of the equipment, as the feedforward power compensation amount.

[0025] Preferably, in step S105, the process of solving the dynamic feedback adjustment amount is as follows: within the rolling optimization time domain, the combined optimization objective is to minimize the sum of squares of the tracking error of the actual temperature data of the material bed and the minimum change amplitude of the control increment. The opening change rate and opening extreme value of the gas regulating valve in the heating regulation mechanism are used as boundary constraints. The dynamic feedback adjustment increment corresponding to each heating zone in each control cycle is solved as the dynamic feedback adjustment amount.

[0026] Preferably, the heating regulation mechanism includes a gas regulating valve and a combustion-supporting fan, and the heating drive signal includes a gas regulating valve drive signal and a combustion-supporting fan frequency conversion drive signal. A dynamic timing decoupling logic is set between the gas regulating valve drive signal and the combustion-supporting fan frequency conversion drive signal. When the total heating power command increases by a step, the combustion-supporting fan frequency conversion drive signal is controlled to lead the output of the gas regulating valve drive signal. When the total heating power command decreases by a step, the gas regulating valve drive signal is controlled to lead the output of the combustion-supporting fan frequency conversion drive signal, thereby maintaining the preset micro-positive pressure and oxidizing atmosphere in the furnace.

[0027] Preferably, it also includes: when the feed mass flow rate is detected to drop to or below the preset safety lower limit threshold, forcibly clearing the dynamic heat absorption disturbance heat and cutting off the feedforward spatial mapping relationship; switching the heating control mode of each heating zone to a constant temperature waiting mode based solely on the equipment insulation reference heat load, and stopping the issuance of heating drive signals superimposed with feedforward power compensation.

[0028] Preferably, the method further includes: calculating an axial thermal crosstalk correction term based on the gas phase temperature gradient between adjacent heating zones in the calcination equipment and the material flow direction; and superimposing the axial thermal crosstalk correction term when calculating the feedforward power compensation to eliminate the axial multi-temperature zone thermal dynamic coupling effect caused by countercurrent heat transfer.

[0029] Preferably, it further includes: during a continuous temperature control cycle, acquiring the residual value between the equipment shell temperature data collected by the infrared thermal imaging temperature measurement device and the theoretical equipment shell temperature data calculated based on the radial heat transfer correlation; when the residual value continuously exceeds the preset allowable deviation range, triggering an adaptive update of the equivalent thermal conductivity parameter of the equipment lining in the radial heat transfer correlation, and recalculating the actual temperature data based on the updated equivalent thermal conductivity parameter.

[0030] A temperature control system for the calcination and activation process of a composite defluorinating agent, comprising a method for controlling the temperature during the calcination and activation process of the composite defluorinating agent, including: The data acquisition module is used to acquire data on the operating speed of the roasting equipment, the feed mass flow rate, the axially distributed gas phase temperature, the exhaust moisture content, and the equipment shell temperature. The temperature inversion calculation module is used to calculate the dynamic angle of repose and heat exchange area of ​​the material based on the radial heat transfer relationship between the equipment shell, the gas phase and the material bed, combined with the operating speed, and to invert and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and the equipment shell temperature data. The heat absorption disturbance calculation module is used to calculate the dynamic heat absorption disturbance of the current activation reaction zone based on the rate of change of feed mass flow rate and flue gas moisture content over time, combined with the enthalpy of dehydration phase change reaction. The feedforward spatial mapping module is used to calculate the advance time constant characterizing the axial migration rate of the material based on the operating speed, establish the feedforward spatial mapping relationship based on the acquisition location of the gas phase temperature data, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the advance time constant, and calculate the feedforward power compensation amount corresponding to each heating zone. The feedback optimization and drive module is used to input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve for the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate the heating drive signal, and output the heating drive signal to the heating regulation mechanism corresponding to each heating zone.

[0031] Example 1: In an industrial-grade rotary kiln for alumina-zirconia composite defluorinating agent with a length of 18m, an inner diameter of 1.4m, and a processing capacity of 1200kg / h, the material passes sequentially from the feed end to the discharge end through a 5m long preheating section, an 8m long main activation section, and a 5m long stabilization section. The target control temperature of the main activation section is set at 520℃, and the control sampling period is set at 5s. Because the composite defluorinating agent precursor is temperature-sensitive during the preheating and dehydration, main phase activation and dehydroxylation, and lattice stabilization stages, the activation temperature range is limited to 400℃ to 650℃. Temperatures below 400℃ cause insufficient removal of surface-active hydroxyl groups, reducing the defluorination capacity. Local temperatures exceeding 650℃ induce high-temperature sintering of the matrix and collapse of mesoporous channels. Simultaneously, the thick tumbling material layer contains thermal resistance, and the gas phase temperature sensor exhibits a time lag in detecting the internal thermal state of the material layer. At specific operating times… The data acquisition module collects the operating speed of the equipment. The mass flow rate is 2.5 rpm for wet-based feed. The time-series signal showing a velocity of 0.333 kg / s and a flue gas moisture content that jumps from 8.2% in the previous sampling period to 9.8%, along with the ambient temperature, is also relevant. This refers to the gas phase temperature data at 22℃ and 8m in the main activation section. The data includes 568℃ and the temperature of the equipment casing. The temperature is 142℃; the temperature inversion calculation module is based on the radial heat transfer relationship between the equipment shell, the gas phase and the material bed, combined with the operating speed. Calculate the dynamic angle of repose of the material The angle is 38.5°, and the corrected gas-fuel heat exchange area is [value missing]. Heat exchange area with wall material The ratio is 1.25, which is the comprehensive heat dissipation convection coefficient from the kiln surface to the external environment. The thermal conductivity is 18.5 W / (m²·K) and the thermal conductivity of the equipment lining. The thermal conductivity is 8.4 W / (m²·K). The temperature data of the inner wall of the equipment lining is obtained by inverse calculation based on the differential relationship of thermal conductivity. Combined with the radiative-convective heat transfer coefficient from the gas phase to the surface of the material bed The contact heat transfer coefficient between the inner wall and the material layer is 45.2 W / (m²·K). A radial node thermal balance equation was constructed for 78.6 W / (m²·K), and the actual temperature data of the material bed in the main activation section along the axial direction was calculated by decoupling. The temperature is 512.4℃. To eliminate the phase lag of the gas phase temperature measurement signal on the true thermal state of the thick material layer, specifically, the radial node heat balance equation is composed of the convective and radiative heat transfer flux from the gas phase to the material bed surface and the contact heat transfer flux from the inner wall of the lining to the material bed. Within the steady-state micro-element, the heat flow from the gas phase to the material surface is equal to the product of the gas-material comprehensive heat transfer coefficient, the effective contact heat transfer area of ​​the gas and material, and the difference between the gas phase temperature and the material bed temperature. The heat flow from the inner wall to the material bed is equal to the product of the wall material contact heat transfer coefficient, the effective contact heat transfer area of ​​the wall material, and the difference between the inner wall temperature and the material bed temperature. The product of the temperature differences between the material bed layers; based on the ratio of gas-material area to wall material area of ​​1.25 after correction for a dynamic packing angle of 38.5°, the heat transfer flux from the gas phase to the material and the heat transfer flux from the wall material to the material are linearly added together and set to equal the total heat flow absorbed by the material bed layer per unit time; by substituting the measured gas phase temperature of 568℃ and the inversely derived inner wall temperature of 406.2℃, the analytical solution of the average temperature of the material bed layer is directly obtained by using the one-dimensional algebraic elimination method to solve the two heat flow relationships simultaneously, thereby completing the online decoupled calculation of the actual temperature at each temperature measurement node.

[0032] When fluctuations in the moisture content of the feed at the feed end cause a sudden increase in the heat absorption and dehydration load, the heat absorption disturbance calculation module calculates the heat absorption disturbance based on the feed mass flow rate. The instantaneous bound water mass fraction of the material was determined by measuring the differential change rate of the flue gas moisture content at a rate of 0.333 kg / s. The conversion factor for the dehydroxylation activation reaction is 0.065. The value is 0.024, based on the latent heat of vaporization during the phase change of water. The standard reaction enthalpy for surface hydroxyl removal is 2257 kJ / kg. Using 1180 kJ / kg as the enthalpy standard for the dehydration phase change reaction, the relationship is calculated based on the dynamic endothermic disturbance heat: ,in, The mass flow rate of the material entering the activation temperature zone, The instantaneous mass fraction of bound water in the material; The latent heat of vaporization during the phase change of water. It is the conversion factor for the dehydroxylation activation reaction; To determine the standard enthalpy of surface hydroxyl removal, the dynamic endothermic disturbance heat corresponding to the current activated reaction zone is calculated. With a power of 58.28 kW, during the analysis of the time sequence signal of flue gas moisture content, due to the different dehydration temperature ranges of free water on the material surface and the internal hydroxyl condensation reaction, the preheating section is mainly characterized by the evaporation of free water, while the main activation section is mainly characterized by the release of dehydroxylated bound water.

[0033] Based on the first derivative of the feed flow rate and flue gas moisture content over time, and combined with the nominal exhaust volume of the kiln tail exhaust fan and the conservation relationship of the molar mass of water vapor in the gas phase, the differential increase rate of flue gas moisture content is first converted into the instantaneous water vapor precipitation mass flow rate of the entire kiln. Then, based on the activation temperature range of 400℃ to 650℃ where the current temperature measurement node is located, and after deducting the estimated free water precipitated in the low-temperature preheating section, the instantaneous bound water mass fraction of the material is directly calculated from the ratio of the net increase rate of water vapor precipitation to the mass flow rate of the material entering this zone. Furthermore, based on the stoichiometric ratio of hydroxyl removal and the material activation reaction rate constant in this temperature range, the reaction water generated per unit time is converted into a dehydroxylation activation reaction conversion rate factor, completing the decoupling calculation of the two parts of disturbance heat: phase change endothermic and chemical reaction endothermic. The feedforward space mapping module is based on the operating speed. The inner radius corresponding to 2.5 rpm and an inner diameter of 1.4 m for the equipment. Given a kiln inclination angle of 0.7m, calculate the axial propulsion velocity of the material particles during their tumbling movement. Multiply this axial propulsion velocity by the response delay time of the heating regulation mechanism to obtain the spatial displacement lead; the lead time constant. The ratio of the axial distance between the gas phase temperature data acquisition location and the data input node of the downstream adjacent predicted heating zone to the axial advance linear velocity is used to characterize the time required for the material to migrate from the acquisition location to the corresponding downstream node. This advance time constant is used to determine the timing of the advance allocation of the perturbation heat to the downstream adjacent predicted heating zone. A one-dimensional feedforward spatial mapping relationship is established using a one-dimensional feedforward spatial phase advance mapping matrix to calculate the dynamic endothermic perturbation heat obtained from the current temperature zone. The data input nodes of the downstream adjacent predicted heating zone are projected in advance according to the mapping weight; the feedforward power compensation calculation logic substitutes the projected dynamic heat absorption disturbance into the axial one-dimensional unsteady heat transfer energy balance equation, combined with the average specific heat capacity of the composite defluorinating agent. The target heating rate is 1.05 kJ / (kg·K). The combustion heat transfer efficiency factor is 0.05℃ / s. Given a value of 0.72 and an effective heat dissipation area of ​​15.8 m² in this temperature range, the convective heat loss from the equipment surface to the external environment is 35.08 kW. Based on the feedforward power compensation formula: ,in, The efficiency factor for heat transfer during combustion; The specific heat capacity of the composite defluorinating agent. Axial position The actual temperature of the material bed at that location. The overall heat dissipation and convection coefficient from the equipment surface to the external environment. The actual measured temperature of the equipment casing. Given the ambient temperature, the feedforward power compensation required to offset the heat absorption during material dehydration and the heat dissipation from the equipment is calculated in reverse. The power output is 129.69 kW. To overcome the in-situ overheating and downstream under-temperature misalignment caused by the spatial transfer of the peak heat absorption due to material tumbling and flow, the feedforward power compensation is further derived based on the axial one-dimensional unsteady heat transfer energy balance equation. Within the axial micro-element control body, the sensible heat rise power of the material entering the temperature zone is determined by the product of the material mass flow rate, average specific heat capacity, and target heating rate. The phase change heat absorption load is directly given by the dynamic heat absorption disturbance heat. For the convective heat loss from the equipment surface to the external environment, the calculation will comprehensively consider... The product of the heat dissipation convection coefficient and the difference between the measured temperature of the outer shell and the ambient temperature, multiplied by the effective heat dissipation surface area of ​​the outer shell corresponding to the current heating zone, 15.8 m², yields a total heat dissipation loss power of 35.08 kW. This ensures that the sensible heat rise term, the latent heat of phase change term, and the outer shell heat dissipation term are all unified in terms of kW thermal power. By summing the above three heat loads and dividing by the combustion heat transfer efficiency factor of 0.72, the feedforward power compensation amount required by the heating regulation mechanism in this temperature zone, 129.69 kW, can be accurately calculated in reverse.

[0034] The feedback optimization and drive module will use the actual temperature data of the material bed in the main activation section. The target value for activation temperature is 512.4℃. Perform a differential calculation at 520℃ to obtain the residual temperature deviation. The temperature is 7.6℃. Within the rolling optimization time domain, the joint optimization objectives are to minimize the sum of squared errors in the actual material bed temperature tracking and to minimize the amplitude of the control increment change. The rate of change of the gas regulating valve opening and the extreme value of the opening are used as boundary constraints, combined with the calibration gain. The value is 1.85 kW / ℃ and the differential prediction time constant. Solve for the dynamic feedback adjustment increment in 12s The power output is 15.46kW, which is used as the dynamic feedback adjustment value; the system will use the feedforward power compensation value. With dynamic feedback adjustment Linear superposition generates total heating power command Its value is 145.15kW. The gas mass flow rate setpoint is calculated based on the lower heating value of natural gas of 35.8MJ / m³. The output is 14.59 m³ / h, and the combustion air volume is automatically proportioned to 153.2 m³ / h according to the theoretical air-fuel ratio of 1:10.5. Dynamic timing decoupling logic is implemented between the gas regulating valve drive signal and the combustion air frequency converter drive signal. When the total heating power command increases by a step, the combustion air frequency converter drive signal is controlled to lead the gas regulating valve drive signal output; conversely, when the total heating power command decreases by a step, the gas regulating valve drive signal is controlled to lead the combustion air frequency converter drive signal output, maintaining a slight positive pressure and a stable oxidizing atmosphere within the furnace. During continuous operation, when the residual between the equipment shell temperature data collected by the infrared thermal imaging temperature measurement device and the theoretical equipment shell temperature data calculated based on the radial heat transfer correlation continuously exceeds the preset allowable deviation range, this residual is used as the identification error, and a recursive least squares method is employed to re-evaluate the radial heat transfer correlation. The system updates the equivalent thermal conductivity parameters of the equipment lining online and recalculates the actual temperature data based on the updated parameters. When the material feed rate suddenly drops to the safety lower limit threshold or below, the control system automatically clears the dynamic heat absorption disturbance and cuts off the feedforward spatial mapping relationship, strips the latent heat of phase change heating component, stops sending the heating drive signal superimposed with feedforward power compensation, and switches to a constant temperature waiting mode based solely on the equipment insulation reference heat load. The equipment insulation reference heat load is taken as the steady-state heating load calibration value when the temperature of each heating zone is stable at the target value under the kiln body no-load constant speed state. After switching, the temperature of each heating zone is maintained accordingly to suppress the transient temperature rise overshoot caused by thermal inertia, so that the particle bed temperature is within the tolerance zone of the target value ±3.5℃, avoiding the collapse of the mesoporous structure of the composite defluorinating agent and the deactivation of the microcrystalline phase change.

[0035] Example 2: This example uses an industrial-grade rotary kiln for alumina-zirconia composite defluorinating agent, with a length of 18m, an inner diameter of 1.4m, and a rated processing capacity of 1200kg / h. Continuous operation testing was conducted on the heat supply control during the multi-temperature zone roasting and activation process. The test platform was equipped with an infrared moisture analyzer for kiln tail exhaust gas with a measurement range of 0-25%, a resolution of 0.05%, and an accuracy of ±0.1%. Six K-type armored gas phase thermocouple sensor arrays with a measurement accuracy of ±0.5℃ and a time constant of no more than 1.5s were arranged along the kiln body axis. An axial infrared temperature sensor array for the kiln shell with a measurement range of 0-400℃ and a temperature measurement accuracy of ±1℃ was arranged along the outer wall of the kiln. An electronic belt scale with dynamic metering accuracy better than ±0.2% was installed at the feed end. The industrial control computer used monitoring software, which included a data acquisition module, a temperature inversion calculation module, a heat absorption disturbance calculation module, a feedforward space mapping module, and a feedback optimization and driving module. The system sampling period was... The determination is based on the axial physical displacement velocity of the material and the hysteresis of heat load conduction; when the sampling period is greater than 10s, it is difficult to capture the differential change in flue gas moisture content corresponding to the transient phase change dehydration peak; when it is less than 1s, high-frequency noise oscillation will be introduced into the dead zone of the actuator. Discretized time-domain response analysis will then... The time was set to 5 seconds. During a 72-hour continuous operation test, the moisture content of the wet-based feed at the feed end changed stepwise within the range of 4% to 11.5%, and the rotation speed varied between 2 rpm and 3 rpm. Intermediate state quantities and control outputs under each control mode were continuously collected. The pore structure parameters and fluoride ion saturation adsorption capacity of the composite defluorinating agent exiting the kiln were sampled and tested. The main activation section used 520℃ as the target control temperature, and the Arrhenius kinetic reaction rate constant at this temperature was used as the calculation benchmark for the dehydroxylation activation reaction conversion rate factor. The monitoring software combined the actual temperature data of the material bed along the axial direction with the axial residence time of the material in the activation zone to calculate the theoretical molar reaction share of hydroxyl removal per unit time, and obtained a dehydroxylation activation reaction conversion rate factor of 0.024, which was used to quantify the transient disturbance component of the dehydroxylation reaction endothermic effect on the total heating load.

[0036] In test groups 1 to 4 employing a complete control link, the operating speeds of test groups 1 and 2 were... Both are 2.5 rpm, wet basis feed mass flow rate Both were 0.333 kg / s. Experimental group 3 had an operating speed of 2 rpm and a wet-based feed mass flow rate of 0.267 kg / s, while experimental group 4 had an operating speed of 3 rpm and a wet-based feed mass flow rate of 0.4 kg / s; the corresponding material bound water mass fractions were... The values ​​are 0.065, 0.095, 0.04, and 0.08, respectively. The time-series change rates of flue gas moisture content are +0.32% / s, +0.68% / s, -0.15% / s, and +0.55% / s, respectively. Based on the above inputs, the heat absorption disturbance calculation module obtains dynamic heat absorption disturbance heat of 58.28kW, 80.83kW, 33.72kW, and 81.82kW, respectively. The temperature inversion calculation module simultaneously obtained the actual axial temperature data of the material bed at 512.4℃, 508.6℃, 516.5℃, and 509.1℃. Based on this, the feedforward space mapping module and the heating load calculation respectively provide feedforward power compensation amounts of 129.69kW, 161.01kW, 87.65kW and 167.34kW. The feedback optimization and drive module outputs dynamic feedback adjustment values ​​of 15.46kW, 22.49kW, 7.86kW, and 21.57kW respectively. After each group completed feedforward and feedback regulation, the temperature fluctuation range of the main activation section bed was 2.8℃, 3.3℃, ​​2.2℃ and 3.5℃, respectively, and the temperature control response delay time was 4.8s, 5.2s, 4.5s and 5.5s, respectively. The mesoporous specific surface area retention rates of the corresponding kiln samples were 94.2%, 92.8%, 95.6% and 91.9%, respectively, and the saturated adsorption capacities of fluoride ions were 15.2mg / g, 14.9mg / g, 15.4mg / g and 14.8mg / g, respectively.

[0037] The aforementioned temperature control response delay time is a statistical calculation of the time taken for the kiln tail sensor to capture the sudden change signal of flue gas moisture content, complete the algorithm calculation, and drive the gas regulating valve and combustion fan to generate the corresponding heat power output. It does not take the macroscopic relaxation time of the thick-walled refractory lining reaching global thermal equilibrium as the timing endpoint. Under the action of the feedforward spatial mapping relationship, the system has already adjusted the burner power tens of seconds in advance before the material particles migrate to the downstream adjacent predicted heating zone, and pre-input the heat into the furnace gas phase and surface material. After the high heat-absorbing material reaches the corresponding heating zone, this part of the heat corresponds to the phase change heat-absorbing load, so that the temperature of the tumbling bed is kept within the target value ±3.5℃ during the step change of moisture, and the mesoporous specific surface area and fluoride ion adsorption performance corresponding to the experimental group are maintained.

[0038] Control group 1 and experimental group 1 used the same operating speed, wet-basis feed mass flow rate, material bound water mass fraction, and flue gas moisture content temporal change rate. However, the dynamic endothermic disturbance heat was not calculated, the actual temperature data of the material bed along the axial direction was not retrieved, the feedforward power compensation was 0 kW, and the dynamic feedback adjustment was 38.6 kW. Under this control state, the temperature fluctuation range of the main activation section bed was 18.6℃, the temperature control response delay time was 46.2 s, the mesoporous specific surface area retention rate was 68.4%, and the fluoride ion saturated adsorption capacity was 10.8 mg / g. The operating input, dynamic endothermic disturbance heat, actual temperature data, and feedforward power compensation of control group 2 were the same as those of experimental group 2. With identical data, the dynamic feedback adjustment was 18.2 kW, resulting in a bed temperature fluctuation range of 14.2℃, a temperature control response delay of 28.5 s, a mesoporous specific surface area retention rate of 74.5%, and a fluoride ion saturation adsorption capacity of 11.9 mg / g. The operating input, dynamic endothermic disturbance heat, and feedforward power compensation of control group 3 were the same as those of experimental group 1, but the actual temperature data of the material bed along the axial direction was not retrieved, and the dynamic feedback adjustment was 8.4 kW; its bed temperature fluctuation range was 11.5℃, the temperature control response delay was 22 s, the mesoporous specific surface area retention rate was 79.1%, and the fluoride ion saturation adsorption capacity was 12.6 mg / g.

[0039] The operating speed of control group 4 was 2.5 rpm, the wet-basis feed mass flow rate was 0.333 kg / s, the bound water mass fraction of the material was 0.135%, and the time-series change rate of flue gas moisture content was +1.25% / s. The heat absorption disturbance calculation module obtained 110.89 kW of dynamic heat absorption disturbance, and the temperature inversion calculation module obtained the actual temperature data of 496.2℃. The corresponding feedforward power compensation was 202.76 kW, and the dynamic feedback adjustment was 41.5 kW. Under this operating condition, the... The maximum heating rate of the burner and the heat exchange capacity of the furnace limit the feedforward power compensation to saturation. The temperature fluctuation range of the main activation section bed is 8.8℃, the temperature control response delay time is 12.4s, the mesoporous specific surface area retention rate is 82.3%, and the saturated adsorption capacity of fluoride ions is 13.1mg / g. The operating input, dynamic endothermic disturbance heat, actual temperature data, feedforward power compensation, and dynamic feedback adjustment of control group 5 are the same as those of the corresponding data of experimental group 1, but the lead time constant is changed. The value was artificially set to deviate from the standard calculation value by 50%; the projection position of the feedforward power compensation on the spatial grid resulted in phase mismatch, generating 8.6kW of axial thermal crosstalk between heating zones, increasing the bed temperature fluctuation range to 12.1℃, with a temperature control response delay of 24.8s, a mesoporous surface area retention rate of 76.2%, and a fluoride ion saturation adsorption capacity of 12.2mg / g. The operating input, dynamic endothermic disturbance heat, actual temperature data, feedforward power compensation, and dynamic feedback adjustment of control group 6 were the same as those of experimental group 1, but dynamic time-series decoupling logic was not used; during the step heating power process, the gas flow rate increased before the combustion air flow rate, and a transient reducing atmosphere and slight negative pressure fluctuation appeared in the furnace. The bed temperature fluctuation range of its main activation section was 6.4℃, the temperature control response delay was 8.6s, the mesoporous surface area retention rate was 86.5%, and the fluoride ion saturation adsorption capacity was 13.8mg / g.

[0040] In the aforementioned continuous tests, experimental groups 1 to 4 all used the time-series change rate of flue gas moisture content and the mass flow rate of feed to form dynamic endothermic disturbance heat input. The feedforward power compensation was pre-allocated to the downstream adjacent predicted heating zone according to the feedforward spatial mapping relationship, and the actual temperature data of the material bed along the axial direction participated in the feedback adjustment. Each group maintained the target temperature tolerance range under the condition of sudden change in moisture content. At the same time, the corresponding mesoporous specific surface area retention rate and fluoride ion saturated adsorption capacity did not show the decrease that occurred in the control group due to the absence of control link, advance time deviation or limited heating capacity. The microporous lattice structure and fluoride ion adsorption activity of the kiln-exit composite defluorinating agent remained stable between consecutive batches.

[0041] Example 3: In the monitoring system of a rotary roasting kiln for alumina-zirconia composite defluorinating agent with a length of 18m, an inner diameter of 1.4m, and a processing capacity of 1200kg / h, the feedforward spatial mapping module is based on the radius inside the kiln. The axial tilt angle of the rotary kiln installation is 0.7m. 1.8° and operating speed The speed is 2.5 rpm, combined with the dynamic angle of repose of the material. A geometric motion model for the axial propulsion of particles in the tumbling material layer was established at 38.5°, and the axial propulsion linear velocity of the particles along the kiln length was calculated. The response delay time of the gas regulating valve and combustion fan in the heating regulation mechanism from receiving the control command to the stable transfer of heat flux in the furnace is 0.015 m / s. The time is 20 seconds, from which the spatial displacement lead of the current control cycle is obtained. : After the material particles are lifted to a dynamic repose angle of 38.5° by the rotation of the kiln wall, they roll down along the surface of the material layer and undergo axial displacement under the influence of the component of gravity along the 1.8° axial tilt direction. The axial advance distance of the particles in a single rotation cycle is determined by pi, the kiln inner diameter of 1.4m, the tangent of the tilt angle, and the sine of the dynamic repose angle. The displacement per cycle is then multiplied by the operating speed of 2.5rpm and converted to seconds to obtain an axial advance linear velocity of 0.015m / s. The monitoring software uses an axial discrete grid step size of 1m. Divide the kiln body into multiple temperature zones and adjust the spatial displacement in advance. Projecting onto the axial mesh nodes yields the mapping weights projected onto the adjacent downstream predicted heating zones. And the mapping weights retained in the current heating zone : The one-dimensional feedforward spatial phase lead mapping matrix adopts a double-diagonal square matrix with the number of axial discrete grid nodes as the dimension. The main diagonal elements correspond to a mapping weight of 0.7 for the current heating zone, and the secondary diagonal elements below the main diagonal correspond to a mapping weight of 0.3 for the downstream adjacent predicted heating zone. The elements at other non-adjacent node positions are set to 0. When a heating zone generates dynamic heat absorption disturbance, the disturbance heat vector of each heating zone is multiplied by this mapping matrix, so that the dynamic heat absorption disturbance heat is distributed between the current heating zone and the downstream adjacent predicted heating zone according to the above mapping weights. The heat absorption disturbance calculation module is based on the feed mass flow rate at the feed end. Output the dynamic endothermic disturbance heat of the current activated reaction zone, along with the time-series change rate of flue gas moisture content. Then, the feedforward space mapping module follows The corresponding disturbance is projected in advance to the data input node of the downstream adjacent predicted heating zone. The high-temperature flue gas in the rotary kiln flows counterclockwise from the kiln head to the kiln tail, with a flue gas velocity of 2 m / s to 3 m / s. The gas phase flow delay of the flue gas generated by moisture evaporation from the reaction zone to the kiln tail exhaust gas detection position is 2 s to 3 s. The material is axially advanced from the feed end to the discharge end at 0.015 m / s. It takes tens to hundreds of seconds for high moisture content material to reach the downstream adjacent predicted heating zone from the upstream. After the moisture content at the feed end or preheating zone fluctuates, the moisture content of the kiln tail exhaust gas responds first. The heat absorption disturbance calculation module obtains the dynamic heat absorption disturbance heat after deducting the 2 s to 3 s gas phase transmission delay. The feedforward space mapping module then allocates the disturbance in advance to the downstream adjacent predicted heating zone according to the axial advancement process of the material, so that the heating adjustment action arrives at the heating zone before the corresponding material.

[0042] During continuous production and calcination, when the kiln lining refractory material is subjected to long-term thermal shock or the thickness of the material layer adhering to the inner wall changes, the temperature inversion calculation module adaptively updates the equivalent thermal impedance parameter of the equipment lining in the radial heat transfer correlation based on the residual between the equipment shell temperature data and the theoretical equipment shell temperature data. The data acquisition module follows a 5-second sampling period. The equipment casing temperature data is simultaneously acquired from the infrared temperature sensor array on the outer wall of the kiln shell. Axial vapor phase temperature data The temperature inversion calculation module calculates the ambient temperature as 22℃. With a nominal heat dissipation convection coefficient of 18.5 W / (m²·K) Substituting the steady-state thermal resistance and heat conduction equation of the kiln lining, we obtain the theoretical equipment shell temperature data. And calculate the temperature residual. : The allowable temperature deviation threshold for the equipment casing is set at 3℃; when the temperature residual... Continuously exceeding this threshold When the decision time window is 12 sampling periods, the control software initiates online recursive least squares identification to determine the thermal conductivity of the equipment lining. The thermal conductivity parameters of the kiln lining material are used in steady-state thermal resistance calculations, while online identification uses the equivalent thermal impedance parameters of the equipment lining. As an update variable, the algorithm aims to minimize the sum of squared residuals between the equipment casing temperature data and the theoretical equipment casing temperature data over 12 consecutive sampling periods within a rolling time window. It uses an observation gain vector formed by the lining thickness, heat dissipation coefficient, and ambient temperature, and constructs a regression input sequence from the gas phase temperature data and equipment casing temperature data at each sampling time. The forgetting factor for the recursive least squares algorithm is set to 0.98, and the equivalent thermal conductivity parameters of the equipment lining are considered. Perform a single-step recursive update; when the relative change in the parameter correction is less than 0.5% in three consecutive iterations, update the equivalent thermal conductivity parameter of the equipment lining. The radial heat transfer correlation was applied based on a three-node thermal resistance network model, and the temperature data of the inner wall of the equipment lining were recalculated. Actual temperature data of the material bed along the axial direction .

[0043] During the multi-temperature zone operation of the counter-flow roasting kiln, the monitoring software determines the direction of the axial thermal crosstalk correction term based on the gas phase temperature gradient between adjacent heating zones and the material flow direction from the feed end to the discharge end. It also calculates the axial thermal crosstalk correction power in conjunction with the flue gas mass flow rate. The gas phase temperature gradient between adjacent temperature measurement nodes is as follows: The axial thermal crosstalk correction power is: ,in, The axial coupling thermal conductivity is calibrated based on the specific heat capacity and flow velocity of the flue gas; the monitoring software determines the direction of power application for correction between adjacent heating zones according to the material flow direction, and... Superimposed on feedforward power compensation The wet-based feed mass flow rate collected by the electronic belt scale at the feed end When the feed rate drops to 0.05 kg / s and remains so for more than 3 sampling cycles, the system determines that the feed has been interrupted, and the heat absorption disturbance calculation module will dynamically calculate the heat absorption disturbance. The data projection of the feedforward spatial mapping relationship is set to zero and cut off. The total heating power command of each heating zone is switched to a constant temperature waiting mode based solely on the equipment insulation reference heat load. The equipment insulation reference heat load already includes the heating load required to compensate for surface heat dissipation under stable kiln insulation conditions. The heat loss of the kiln surface is no longer used as an independent additional control input. When the total heating power command is reduced, the dynamic timing decoupling logic controls the gas regulating valve drive signal to be output before the combustion air frequency conversion drive signal, so that the heating regulation mechanism completes the gas and combustion air regulation in the direction of power reduction and maintains the main activation temperature zone of the rotary kiln within the range of 520℃ target value ±3.5℃.

[0044] Example 4: This example combines Figures 1 to 2 This paper describes a temperature control method and system for the calcination and activation process of a composite defluorinating agent, such as... Figure 1 As shown, the temperature control method executes step S101, acquiring the operating speed of the roasting equipment, feed mass flow rate, axially distributed gas phase temperature data, flue gas moisture content, and equipment shell temperature data. Then, step S102 is executed, calculating the dynamic angle of repose and heat transfer area of ​​the material based on the radial heat transfer relationship between the equipment shell, the gas phase, and the material bed, combined with the operating speed. The actual axial temperature data of the material bed is calculated based on the gas phase temperature data and the equipment shell temperature data. Finally, step S103 is executed, calculating the dynamic angle of repose and heat transfer area of ​​the current activation reaction zone based on the rate of change of feed mass flow rate and flue gas moisture content over time, combined with the enthalpy reference of the dehydration phase change reaction. The process begins by absorbing heat from the dynamic endothermic disturbance. Next, step S104 is executed, where a lead time constant, representing the axial migration rate of the material, is calculated based on the operating speed. A feedforward spatial mapping relationship is established using the gas phase temperature data acquisition location as a reference. The dynamic endothermic disturbance heat is pre-allocated to the downstream adjacent predicted heating zones according to the lead time constant. The feedforward power compensation for each heating zone is calculated. Finally, step S105 is executed, where the deviation between the actual temperature data and the target activation temperature is input into the predictive control model to solve for the dynamic feedback adjustment. The feedforward power compensation and the dynamic feedback adjustment are superimposed to generate a heating drive signal, which is then output to the heating regulation mechanism corresponding to each heating zone.

[0045] like Figure 2As shown, the temperature control system includes a data acquisition module, an endothermic disturbance calculation module, a feedback optimization and drive module, a temperature inversion calculation module, and a feedforward space mapping module, which are jointly applied to the temperature control of the composite defluorinating agent calcination and activation process. Specifically, the data acquisition module acquires operating speed, flue gas moisture content, and equipment shell temperature data; the temperature inversion calculation module calculates the actual temperature data based on radial heat transfer correlation and the dynamic angle of repose of the material; the endothermic disturbance calculation module calculates the dynamic endothermic disturbance heat by combining the enthalpy reference of the dehydration phase change reaction and the conversion rate factor of the dehydroxylation activation reaction; the feedforward space mapping module calculates the lead time constant based on the axial propulsion linear velocity and allocates the dynamic endothermic disturbance heat in the feedforward space to calculate the feedforward power compensation; the feedback optimization and drive module solves for the dynamic feedback adjustment based on the predictive control model and outputs the gas regulating valve drive signal based on the feedforward power compensation, thereby collaboratively completing the temperature control of the composite defluorinating agent calcination and activation process.

[0046] Example 5: In the initial deployment of the alumina-zirconia composite defluorinating agent rotary roasting kiln monitoring system, the system established an initial impedance benchmark database for radial heat transfer correlation through offline stepped temperature rise testing. Under constant speed and no-load operation of the kiln, the data acquisition module controlled the drive motor to change its speed gradient in 0.5 rpm increments within the range of 1.5 rpm to 3.5 rpm. Infrared thermal imaging and axial vapor phase temperature sensors synchronously recorded the temperature response curves at steady state at each speed. The system then fitted the dynamic angle of repose of the material based on the relationship between the kiln's rotational speed and the angle of repose of the material particles. With operating speed A monotonically increasing linear calibration function was used, and a discrete correction table for the gas-to-material heat exchange area ratio was calculated. Subsequently, during the empty kiln heating stage, the gas phase temperature data and the equipment shell temperature data were substituted into a one-dimensional thermal conductivity inversion algorithm to calibrate the thermal conductivity of the equipment lining under an ambient temperature of 22°C without material covering. The coefficient of heat transfer is 8.4 W / (m²·K). Combined with the thermal resistance response of the material bed measured during the small-scale trial feeding phase, the least squares algorithm is used to determine the radiative-convective heat transfer coefficient from the gas phase to the surface of the material bed. The value was revised to 45.2 W / (m²·K), representing the contact heat transfer coefficient between the inner wall of the equipment lining and the material bed. The value was corrected to 78.6 W / (m²·K), thus forming an initial thermal resistance parameter mapping relationship covering the rotational speed range of 1.5 rpm to 3.5 rpm, which is used to calculate the actual temperature data of the material bed along the axial direction.

[0047] To address the overshoot and mechanical wear of the heating regulation mechanism during drastic temperature fluctuations, the feedback optimization and drive module incorporates an explicit quadratic programming solution process and dynamic boundary constraints into the predictive control model. Within each 5-second control sampling cycle, the system inputs the residual vector between the actual axial temperature data of the material bed and the target activation temperature into the state-space prediction model. The prediction time domain is set to 10 sampling cycles, and the control time domain to 3 sampling cycles. Using a convex quadratic functional composed of the tracking error weight matrix and the control increment penalty matrix as the target criterion, the monitoring software limits the maximum opening rate of the gas regulating valve to no more than 2.5% per second, and restricts the absolute upper and lower limits of the valve opening to a safe operating range of 10% to 90%. The optimal control increment sequence is solved discretely and iteratively within a single sampling cycle using an effective set algorithm, with only the first dynamic feedback adjustment increment in the sequence being used as the dynamic feedback regulation amount. Output: When the dynamic feedback adjustment increment solved within two consecutive control cycles causes the total heating power command to reach the extreme value of the physical opening of the gas regulating valve, the system cuts off the integral accumulation term and locks the feedforward power compensation amount. The weight upper limit is set to maintain the gas regulating valve opening and combustion fan frequency at the stable output point corresponding to the target operating condition. The state space prediction model uses the material bed temperature in three temperature zones—preheating section, main activation section, and stabilization section—as the state variable, and the change in the gas regulating valve opening in each temperature zone as the control input variable. The state transition matrix is ​​constructed based on first-order inertia plus pure time delay discretization, where the state diagonal self-decay parameter is 0.92, the thermal coupling influence coefficient between adjacent temperature zones is 0.05, and the diagonal elements of the control input gain matrix are 0.38. In each control cycle, the effective set algorithm uses this discrete state equation as the prediction kernel, transforms the prediction error in the next 10 steps and the sum of squares of the control increment in the next 3 steps into a standard convex quadratic equation system. By solving the linear Karouch-Kun-Tucker equation system, and completing matrix inversion and projection calculations in 4 to 7 iterations within the working effective set constraint boundary, the dynamic feedback adjustment corresponding to the current control cycle is output.

[0048] Example 6: During the multi-temperature zone calcination activation process of the alumina-zirconium hydroxide composite defluorinating agent, the feedback optimization and drive module constructs a dynamic sensitivity matrix through multi-condition step disturbance response during the system initialization phase. This matrix is ​​used for parameter tuning and state convergence of the rolling time-domain optimization feedback algorithm. Under a steady-state baseline with a throughput of 1200 kg / h and a kiln rotation speed of 2.5 rpm, the system applies discrete heating power step test signals of ±5 kW to the heating regulation mechanism of each temperature zone. The dynamic response time delay and heating rate response curves of each temperature zone along the axial direction of the material bed are obtained by the axially distributed temperature measurement array and the temperature inversion calculation module, and the actual temperature data of the material bed along the axial direction are identified. Static gain of heating input power The differential prediction time constant is 1.85 kW / ℃. It lasts for 12 seconds; then during the control cycle... Under the condition of 5s, the rolling optimization time domain is set to 10 sampling steps and the control time domain is set to 3 sampling steps. An objective function is constructed with the sum of squared tracking errors of the material bed temperature and the rate of change of control increment as joint indicators. The error tracking weight coefficient is 1, and the control increment suppression weight coefficient is 0.35. The quadratic programming algorithm solves for the dynamic feedback adjustment amount under the constraint that the rate of change of the gas regulating valve opening does not exceed 2.5% per second. It is used to suppress overshoot oscillations caused by time lag in conventional proportional-integral regulation, so that the actual temperature data of the material bed along the axial direction approaches the target activation temperature of 520℃.

[0049] Under counter-current heat exchange conditions, the axial flow of high-temperature flue gas causes multi-temperature thermal dynamic crosstalk, accompanied by air-fuel ratio fluctuations. The monitoring software uses an axial thermal crosstalk compensation algorithm and dynamic timing decoupling logic for adjustment. The heat absorption disturbance calculation module calculates the axial gas phase temperature gradient based on the gas phase temperature data collected by the gas phase temperature sensors in adjacent heating zones. The direction of action of the axial thermal crosstalk correction term between adjacent heating zones is determined according to the material flow direction from the feed end to the discharge end. Then, the coupling thermal conductivity of the axial thermal crosstalk correction term is determined by combining the flue gas mass flow rate calculated from the frequency conversion command of the exhaust fan. It is 0.42 kW·m / ℃, and then according to Calculate the axial thermal crosstalk correction power to offset the countercurrent gas phase crosstalk. And add it to the feedforward power compensation amount In the actual calibration, the coupling thermal conductivity coefficient was derived from the average constant pressure specific heat capacity of flue gas (1.08 kJ / (kg·K), the operating flue gas mass flow rate (0.26 kg / s), and the cross-sectional area of ​​the kiln body (1.54 m²). This coefficient value is equal to the product of the flue gas mass flow rate and the specific heat capacity, multiplied by the micro-grid span of 1 m. After offline cold flue gas tracer test and fitting correction with multi-temperature zone temperature difference response curve, it was finally calibrated to 0.42 kW·m / ℃. When there is a gas phase temperature gradient between adjacent temperature zones, this coefficient is used to calculate the axial thermal crosstalk correction power to correspond to the thermal disturbance transmitted axially by the counterflow flue gas.

[0050] When the total heating power command is output to the heating regulation mechanism, the system sets a decoupling timing delay between the gas regulating valve drive signal and the combustion air frequency converter drive signal. The timing is 1.2s; when the total heating power command increases by a step, the control signal for the combustion air frequency converter is output 1.2s ahead of the gas regulating valve drive signal; when the total heating power command decreases by a step, the control signal for the gas regulating valve is output 1.2s ahead of the combustion air frequency converter drive signal, maintaining the furnace micro-positive pressure in the range of +15Pa to +25Pa, and stabilizing the residual oxygen volume fraction in the tail gas in the range of 2.5% to 3.8%, avoiding local oxygen deficiency that could create a reducing atmosphere and deplete the hydroxyl active sites on the surface of the defluorinating agent, thus ensuring proper kiln exit. The defluorinating agent completes the removal of structural water and locking of active crystalline phases across the entire temperature range. The 1.2s decoupling time delay is determined based on the dynamic response difference between the 0.3s response dead time of the gas regulating valve angle stroke actuator and the 1.5s fluid transport lag time required for the combustion blower to fully establish air pressure in the pipeline from frequency conversion speed-up. When the power increases stepwise, the combustion blower increases frequency conversion speed 1.2s in advance, so that when the gas flow increases, the corresponding combustion air supply has been formed in the furnace, maintaining the micro-positive pressure oxidation environment required for the activation of the defluorinating agent lattice.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A temperature control method for the calcination and activation process of a composite defluorinating agent, characterized in that, Includes the following steps: Step S101: Obtain the operating speed, feed mass flow rate, axially distributed gas phase temperature data, flue gas moisture content, and equipment shell temperature data of the roasting equipment; Step S102: Based on the radial heat transfer correlation between the equipment shell, gas phase, and material bed, calculate the dynamic angle of repose and heat transfer area of ​​the material in conjunction with the operating speed, and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and equipment shell temperature data; Step S103: Based on the rate of change of feed mass flow rate and flue gas moisture content over time, and in conjunction with the enthalpy of the dehydration phase change reaction, calculate the dynamic endothermic disturbance heat of the current activation reaction zone. Step S104: Calculate the advance time constant characterizing the axial migration rate of the material based on the operating speed, establish a feedforward spatial mapping relationship based on the gas phase temperature data acquisition location, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the advance time constant, and calculate the feedforward power compensation amount corresponding to each heating zone; Step S105: Input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate a heating drive signal, and output the heating drive signal to the heating adjustment mechanism corresponding to each heating zone.

2. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, Step S102 includes the following sub-steps: Step S1021, calculate the inner wall temperature data of the equipment lining based on the equipment shell temperature data, ambient temperature and the thermal conductivity of the equipment lining; Step S1022, construct the radial node heat balance equation based on the convective and radiative heat transfer from the gas phase to the material bed surface and the contact heat transfer from the inner wall of the equipment lining to the material bed; Step S1023, dynamically correct the gas-material heat exchange area and the wall material heat exchange area by combining the dynamic packing angle of the material, and decouple the calculation to obtain the actual temperature data of the material bed along the axial direction corresponding to each temperature measurement node.

3. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, Step S104 includes the following sub-steps: Step S1041, calculate the axial propulsion linear velocity of the material particles during the tumbling process based on the operating speed, the tilt angle of the roasting equipment, and the inner diameter of the equipment; Step S1042, multiply the axial propulsion linear velocity by the preset response delay time of the heating adjustment mechanism to obtain the spatial displacement advance, and determine the mapping weight based on the projection span of the spatial displacement advance in the axial grid; Step S1043, project the dynamic heat absorption disturbance heat calculated in the upstream heating zone to the data input node of the downstream adjacent predicted heating zone according to the mapping weight.

4. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, The calculation of the feedforward power compensation amount for each heating zone in step S104 includes the following sub-steps: Step S1044, inputting the dynamic heat absorption disturbance into the axial one-dimensional unsteady heat transfer energy balance equation, combined with the feed mass flow rate, the average specific heat capacity of the composite defluorinating agent, the target heating rate, and the convective heat loss from the equipment surface to the external environment; Step S1045, calculating the basic thermal power compensation value required to offset the heat absorption of the material dehydration phase change and the convective heat loss of the equipment, as the feedforward power compensation amount.

5. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, In step S105, the process of solving the dynamic feedback adjustment amount is as follows: In the rolling optimization time domain, the combined optimization objective is to minimize the sum of squares of the tracking error of the actual temperature data of the material bed and the minimum change amplitude of the control increment. The opening change rate and opening extreme value of the gas regulating valve in the heating regulation mechanism are used as boundary constraints. The dynamic feedback adjustment increment corresponding to each heating zone in each control cycle is solved as the dynamic feedback adjustment amount.

6. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, The heating regulation mechanism includes a gas regulating valve and a combustion air blower. The heating drive signal includes a gas regulating valve drive signal and a combustion air variable frequency drive signal. Dynamic timing decoupling logic is set between the gas regulating valve drive signal and the combustion air variable frequency drive signal. When the total heating power command increases by a step, the combustion air variable frequency drive signal is controlled to lead the output of the gas regulating valve drive signal. When the total heating power command decreases by a step, the gas regulating valve drive signal is controlled to lead the output of the combustion air variable frequency drive signal, thus maintaining the preset micro-positive pressure and oxidizing atmosphere in the furnace.

7. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, Also includes: When the feed mass flow rate is detected to drop to or below the preset safety lower limit threshold, the dynamic heat absorption disturbance heat is forcibly cleared to zero and the feedforward space mapping relationship is cut off. Switch the heating control mode of each heating zone to a constant temperature waiting mode based solely on the equipment insulation baseline heat load, and stop sending heating drive signals with feedforward power compensation.

8. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, Also includes: Based on the gas phase temperature gradient between adjacent heating zones in the calcination equipment and the material flow direction, the axial thermal crosstalk correction term is calculated. An axial thermal crosstalk correction term is superimposed when calculating the feedforward power compensation to eliminate the influence of axial multi-temperature zone thermal dynamic coupling caused by counterflow heat transfer.

9. The temperature control method for the calcination and activation process of a composite defluorinating agent according to claim 1, characterized in that, Also includes: During the continuous temperature control cycle, the residual value between the equipment shell temperature data collected by the infrared thermal imaging temperature measurement device and the theoretical equipment shell temperature data calculated based on the radial heat transfer correlation is obtained; when the residual value continuously exceeds the preset deviation allowable range, the adaptive update of the equivalent thermal conductivity parameter of the equipment lining in the radial heat transfer correlation is triggered, and the actual temperature data is recalculated based on the updated equivalent thermal conductivity parameter.

10. A temperature control system for the calcination and activation process of a composite defluorinating agent, used to implement the temperature control method for the calcination and activation process of the composite defluorinating agent as described in claim 1, characterized in that, include: The data acquisition module is used to acquire the operating speed of the roasting equipment, the feed mass flow rate, the axially distributed gas phase temperature data, the flue gas moisture content, and the equipment shell temperature data. The temperature inversion calculation module is used to calculate the dynamic angle of repose and heat transfer area of ​​the material based on the radial heat transfer correlation between the equipment shell, the gas phase, and the material bed, combined with the operating speed, and to invert and calculate the actual temperature data of the material bed along the axial direction based on the gas phase temperature data and the equipment shell temperature data. The heat absorption disturbance calculation module is used to calculate the dynamic heat absorption disturbance heat of the current activation reaction zone based on the rate of change of the feed mass flow rate and the flue gas moisture content over time, combined with the enthalpy of the dehydration phase change reaction. The feedforward spatial mapping module is used to calculate the lead time constant characterizing the axial migration rate of the material based on the operating speed, establish a feedforward spatial mapping relationship based on the gas phase temperature data acquisition location, allocate the dynamic heat absorption disturbance heat to the downstream adjacent predicted heating zone in advance according to the lead time constant, and calculate the corresponding feedforward power compensation amount for each heating zone. The feedback optimization and drive module is used to input the deviation between the actual temperature data and the target value of the activation temperature into the predictive control model to solve for the dynamic feedback adjustment amount, superimpose the feedforward power compensation amount and the dynamic feedback adjustment amount to generate the heating drive signal, and output the heating drive signal to the heating regulation mechanism corresponding to each heating zone.

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