A dynamic heat transfer temperature control method for a reactor heating furnace

Abstract

The application discloses a dynamic heat transfer temperature control method for a reaction kettle heating furnace, and relates to the technical field of temperature monitoring.The method comprises the following steps: S1, placing a target reaction kettle and a target heating furnace in a temperature field and marking a first heat conduction area and a second heat conduction area; S2, marking the size of an occupied space block and constructing a heat area evaluation strategy; S3, marking a first-order overheating area; using a time step prediction method to calculate a third heat conduction value; S4, calculating a temperature gradient vector field, generating a second-order overheating area, and adjusting the temperature of the second-order overheating area.The application quantitatively models the flow state of heat between the reaction kettle and the heating furnace, obtains an estimated value of temperature rise change, identifies the direction and intensity of heat migration, realizes spatial positioning and early warning of an upcoming temperature overheating area, can strengthen the spatial forward-looking identification of potential local overtemperature, and makes up for the judgment blind spot of the existing system for temperature rise that has not occurred but will occur.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature monitoring, in particular to a dynamic heat transfer temperature control method for a reaction kettle heating furnace. BACKGROUND

[0002] In a pressure reaction kettle heating system, an external circulating heating furnace is the main core equipment for maintaining high temperature and high pressure reaction. The conventional working process in the prior art is that high temperature heat conducting oil is heated to a set temperature (usually 200-350℃) in an external heating furnace, such as an electric heating heat conducting oil furnace or a gas heat oil furnace, pressurized by a high temperature circulating pump, and then delivered to the reaction kettle jacket or the built-in coil through the heat preservation metal pipeline. The heat medium flows in the reaction kettle heat exchange structure, and the heat is conducted to the internal material through the kettle wall. The cooled heat conducting oil returns to the heating furnace for reheating, forming a closed loop circulation. The existing temperature control system usually adjusts the heating furnace outlet temperature or the heat medium regulating valve opening degree through a regulating algorithm based on the deviation of the kettle temperature sensor data to achieve temperature regulation.

[0003] The existing control system usually only relies on single loop feedback control, or acquires temperature feedback and performs temperature compensation in time series form at a certain frequency. When the reaction in the reaction kettle is intense and the reaction changes are complex, the temperature changes are also more complex, which makes it difficult for the existing temperature control system to dynamically evaluate the coupling relationship between the heat medium flow rate and the temperature decay, resulting in that the monitoring feedback of dynamic heat transfer of each part of the heating furnace, the feedback estimation of the temperature change about to occur in each heating area receiving dynamic heat transfer are not timely, which leads to the decrease of the overall temperature control precision in the reaction kettle heating process, and makes the temperature control response lag and even leads to process out of control. SUMMARY

[0004] The present application provides a dynamic heat transfer temperature control method for a reaction kettle heating furnace, which solves the problem that the existing temperature monitoring technology is not accurate in evaluating the potential temperature change caused by dynamic heat transfer in the heating process when dynamically monitoring and adjusting the temperature of the reaction kettle heating furnace with complex reaction changes, resulting in poor accuracy of the heating furnace temperature monitoring.

[0005] The present application is realized by the following technical scheme:

[0006] A dynamic heat transfer temperature control method for a reaction kettle heating furnace, the method comprising:

[0007] Step S1: constructing a temperature field in a spatial coordinate system, equally dividing the spatial region of the temperature field along the coordinate axis into a plurality of spatial blocks, placing the target reaction kettle and the target heating furnace in the temperature field, and marking the target reaction kettle in the form of spatial blocks to indicate the first heat conduction area representing local overheating, and marking the target heating furnace in the form of spatial blocks to indicate the second heat conduction area representing local overheating;

[0008] Step S2: Mark the size of the spatial block occupied by the first thermal conduction zone and the second thermal conduction zone along the spatial block in the temperature field, and mark the heat energy values ​​in the first thermal conduction zone and the second thermal conduction zone as the first thermal conduction value and the second thermal conduction value respectively, and construct a thermal zone evaluation strategy based on the first thermal conduction value and the second thermal conduction value.

[0009] Step S3: Mark the superheated space blocks in the temperature field that indicate potential dynamic heat transfer in the first thermal conductivity zone using the thermal zone assessment strategy, and mark all superheated space blocks as first-order superheated zones; use the time step prediction method to predict and calculate the thermal energy trend value of each first-order superheated zone based on the first thermal conductivity value and the second thermal conductivity value, and mark it as the third thermal conductivity value.

[0010] Step S4: Calculate the temperature gradient vector field of the corresponding local overheating zone using the third thermal conductivity value in each first-order overheating zone. Use the location pointed to by the temperature gradient vector field to generate a second-order overheating zone with the same spatial size as the first-order overheating zone and representing the end of potential dynamic heat transfer. Perform temperature overheating adjustment on the target reactor part covered by the second-order overheating zone.

[0011] Current control systems struggle to dynamically assess the coupling relationship between heat transfer fluid flow rate and temperature decay when encountering intense and complex reactions in the reactor. This results in delayed monitoring and feedback of dynamic heat transfer in various parts of the furnace, as well as untimely prediction of impending temperature changes in each heated area receiving dynamic heat transfer. Consequently, the overall temperature control accuracy during reactor heating decreases, leading to lag in temperature control response and even process malfunction. Therefore, this invention provides a dynamic heat transfer temperature control method for reactor furnaces. This method addresses the problem of inaccurate assessment of potential temperature changes caused by dynamic heat transfer during heating in reactor furnaces with complex reaction conditions, resulting in poor temperature monitoring accuracy.

[0012] Furthermore, the process of marking the first and second thermally conductive areas includes:

[0013] The process of starting up the target reactor and the target heater is defined as one working cycle. The heating rate threshold and the upper temperature limit threshold are set independently for each spatial block of the target reactor and the target heater. The heating rate and the upper temperature limit of the target reactor and the target heater are monitored during each working cycle. When the heating rate reaches the heating rate threshold or the upper temperature limit reaches the upper temperature limit threshold, it is determined that there is local overheating in the corresponding spatial block.

[0014] The space blocks with local overheating in the target reactor are marked as first heat conduction zones by merging adjacent space blocks; the space blocks with local overheating in the heating furnace are marked as second heat conduction zones by merging adjacent space blocks.

[0015] Further, the content of the heat zone evaluation strategy includes:

[0016] An overheated space threshold is set, and the first heat conduction zone whose heat energy value reaches the overheated space threshold is marked as a first-order overheated zone; the first heat conduction zone and the second heat conduction zone with adjacent contact are merged to set a to-be-detected overheated zone; the first heat conduction value and the second heat conduction value are calculated by weighted summation to obtain a merged heat energy value in the to-be-detected overheated zone, and when the merged heat energy value reaches the overheated space threshold, it is determined that the space blocks of the first heat conduction zone and the second heat conduction zone currently detected are overheated space blocks, and then it is determined that the to-be-detected overheated zone is a first-order overheated zone.

[0017] Further, the calculation process of the third heat conduction value includes:

[0018] Let T represent the real-time temperature value of the temperature field, and t represent the time step; let the first heat conduction value be represented as Q1, the second heat conduction value be represented as Q2, and the third heat conduction value be represented as Q3; let the average material density of the reactor be represented as p, and let the constant-pressure specific heat capacity in the reactor be represented as c ρ , let the ordinal number of the space block be i, and let the volume size of the space block be V; let m represent the heat energy parameter,

[0019] The calculation formula of the third heat conduction value Q3 is: ,

[0020] wherein Q3 (i) in the formula represents the third heat conduction value Q3 of the i-th space block, T i (t+1) in the formula represents the real-time temperature value predicted for the i-th space block at the t+1 time step.

[0021] Further, the process of obtaining the real-time temperature value T i (t+1) predicted at the t+1 time step includes:

[0022] obtaining the current time step real-time temperature value T i tmonitor and collect the reactant flow value after the concentration of the reactant changes and the stirring speed value of the target reactor; in the current time step, the reactant heat load value is calculated using the reactant flow value, and the mechanical heat load value is calculated using the stirring speed value, the reactant heat load value and the mechanical heat load value are updated to the real-time temperature value in the form of addition, and the updated real-time temperature value is set as the real-time temperature value T predicted in the t+1 time step i (t+1) .

[0023] Further, the process of calculating the temperature gradient vector field to generate the second-order superheating zone includes:

[0024] In each first-order superheating zone, a third heat conduction value matrix is constructed, and an initial gradient vector representing the heat transfer direction is calculated based on the third heat conduction value matrix; the fluid simulation rate and the eddy diffusion coefficient of the target reactor are generated using the CFD simulation flow field, and the initial gradient vector is corrected and generated as a corrected gradient vector using the fluid simulation rate and the eddy diffusion coefficient;

[0025] The coordinates of each space block in each first-order superheating zone are marked as first-order block coordinates, and the first-order block coordinates are updated by integral processing along the direction of the corrected gradient vector, and the integral value is correspondingly represented as the second-order space coordinates of each space block completing the heat flow path update, and the temperature field space region composed of each space block corresponding to the second-order space coordinates is marked as a second-order superheating zone.

[0026] Further, the initial gradient vector is calculated using the central difference method, and the process includes:

[0027] For each space block in the x, y, z coordinate directions in the space coordinate system, the x gradient component, the y gradient component and the z gradient component are calculated respectively, and the difference between the third heat conduction values of adjacent space blocks is denoted as a block temperature difference,

[0028] The calculation method of the x gradient component is to take the block temperature difference in the x axis direction and divide it by 2 times the x axis direction step;

[0029] The calculation method of the y gradient component is to take the block temperature difference in the y axis direction and divide it by 2 times the y axis direction step;

[0030] The calculation method of the z gradient component is to take the block temperature difference in the z axis direction and divide it by 2 times the z axis direction step;

[0031] The x gradient component, the y gradient component and the z gradient component are combined to form the initial gradient vector.

[0032] Further, the calculation process of the corrected gradient vector includes:

[0033] Let the modified gradient vector be represented as Yc, let the initial gradient vector be represented as Yo, let the fluid simulation rate be represented as epsilon, and let the eddy diffusion coefficient be represented as lambda, then the calculation formula of the modified gradient vector is: ,

[0034] In the formula, the represents the vector differential of the fluid simulation rate, and the represents the velocity vorticity.

[0035] Further, for the space block where the axial flow agitator of the target reaction kettle is located, the axial step lengths of the x-axis, y-axis and z-axis are all taken as 2 times the radial length of the axial flow agitator.

[0036] Further, when the block temperature difference in the z-axis direction exceeds twice the block temperature differences in the x-axis direction and the y-axis direction, numerical convergence is performed for the z-axis direction step length.

[0037] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0038] 1. The temperature field is constructed in the spatial coordinate system, the heat energy values of the first heat conduction zone and the second heat conduction zone are marked, the flow state of heat between the reaction kettle and the heating furnace is quantitatively modeled, and thus the dynamic evaluation of the potential heat conduction path is realized, and the prediction deficiency of the traditional system in dynamically evaluating the coupling relationship between the heat medium flow rate and the actual heat transfer is alleviated.

[0039] 2. The time step prediction algorithm is used to predict the heat energy trend of the first-order overheating zone in advance, and the estimated value of the temperature rise change is obtained, which is helpful for analyzing the time dynamics of temperature change, improving the response advancement of sudden severe reactions and heat mutations, and enhancing the feedforward regulation capability of the target reaction kettle temperature control system.

[0040] 3. By constructing the temperature gradient vector field, the heat migration direction and intensity are identified, the second-order overheating zone is generated at the end space block of the heat flow direction, the spatial positioning and early warning of the temperature overheating region that will appear are realized, the spatial forward-looking identification of potential local overtemperature is strengthened, and the judgment blind area of the existing system for the temperature rise that has not occurred but will occur is made up. BRIEF DESCRIPTION OF DRAWINGS

[0041] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0042] Figure 1 The flowchart of the present application. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be given to the present application in combination with embodiments and drawings, the illustrative embodiments and the description thereof are only used to explain the present application, and do not limit the present application.

[0044] Embodiment 1, as shown in the figure, is a dynamic heat transfer temperature control method for a reaction kettle heating furnace, the method comprises: Figure 1

[0045] Step S1: constructing a temperature field in a spatial coordinate system, equally dividing the spatial region of the temperature field along the coordinate axis into a plurality of spatial blocks, placing the target reaction kettle and the target heating furnace in the temperature field, marking out the first heat conduction zone representing local overheating in the form of spatial blocks for the target reaction kettle, and marking out the second heat conduction zone representing local overheating in the form of spatial blocks for the target heating furnace;

[0046] Step S2: marking out the size of the spatial blocks occupied by the first heat conduction zone and the second heat conduction zone in the temperature field, and marking the heat energy values in the first heat conduction zone and the second heat conduction zone as the first heat conduction value and the second heat conduction value respectively, and constructing a heat zone evaluation strategy based on the first heat conduction value and the second heat conduction value;

[0047] Step S3: marking out the overheated spatial blocks representing potential dynamic heat transfer in the first heat conduction zone in the temperature field using the heat zone evaluation strategy, marking the overheated spatial blocks as first-order overheated zones; using a time step prediction method to predict and calculate the heat energy trend value of each first-order overheated zone based on the first heat conduction value and the second heat conduction value and marking it as a third heat conduction value;

[0048] Step S4: calculating the temperature gradient vector field of the corresponding local overheated zone using the third heat conduction value in each first-order overheated zone, generating a second-order overheated zone consistent with the spatial size of the first-order overheated zone and representing the end of potential dynamic heat transfer using the position pointed by the temperature gradient vector field, and adjusting the temperature overheating for the target reaction kettle part covered by the second-order overheated zone.

[0049] ​The target reactor is usually composed of a reactor body, a jacket, and an internal coil, etc., and is used to bear chemical reactions under high temperature and high pressure; the jacket or the internal coil circulates heat medium to realize heating or cooling of materials in the reactor. Since reactions are mostly exothermic or endothermic reactions, temperature fluctuation is large, and the temperature control system is required to have high precision and high response speed to ensure process stability and product quality. Temperature change during the reaction process is complex, and local overheating or temperature dead angle is difficult to accurately monitor and control. Traditional temperature control mostly relies on single-point temperature measurement, which cannot reflect the overall temperature field dynamics, and is prone to cause unstable process or safety risks. The target heating furnace usually includes an electrically heated conductive oil furnace or a gas heated oil furnace, which provides stable heat energy input for the reactor by heating conductive oil, and is a core component of an external circulation type heating system. The heat medium conductive oil is pressurized by a high-temperature circulating pump, transported to the reactor jacket or internal coil for heat exchange, returned to the heating furnace for continuous heating after completing heat transfer, and forms a closed loop. The temperature control of the heating furnace generally relies on the outlet temperature or the heat medium valve adjustment, and the feedback signal of temperature change mainly comes from the temperature sensor in the reactor, and the control mode is usually single and has a lagging response.

[0050] In this embodiment, the entire temperature field is divided into spatial grid units of uniform size based on the Cartesian coordinate system, essentially forming a three-dimensional discrete grid structure, and each spatial block represents a voxel unit in space for collecting or simulating the temperature value at that location. The first heat conduction zone refers to all areas in the target reactor that may have local high temperature due to intense reaction, concentrated heat transfer, etc. The second heat conduction zone refers to all areas in the target heating furnace that may have overheating due to furnace structure problems, local heating element power concentration, etc. The number of first heat conduction zones and second heat conduction zones can be multiple, and the "first" and "second" are used for classification. The first-order overheating zone represents a spatial area in the target reactor that has potential abnormal heat energy changes under the combined influence of the first heat conduction zone and the second heat conduction zone, i.e. the overheating spatial block in the first-order overheating zone is taken from the first heat conduction zone; and the second heat conduction zone is used as an auxiliary influencing condition to determine which first heat conduction zone will become an overheating spatial block. The overheating spatial block represents a spatial block in the first heat conduction zone that is abnormally heated, i.e. the overheating spatial block can be a complete first heat conduction zone or a combination of partial spatial blocks from multiple first heat conduction zones. The time step prediction method refers to a numerical method that discretizes the continuous heat conduction process into continuous time steps, and updates the state and predicts the trend at each time step. By taking the current first heat value and second heat value of the reactor and heating furnace as input, the time step method is used to predict the heat energy change trend of each first-order overheating zone at future time, and the trend result is defined as the third heat value of the first-order overheating zone. In specific implementation, the Crank-Nicolson method or finite element method can be used for calculation. Based on the third heat value representing the future heat energy development trend in each first-order overheating zone, a vector field of temperature gradient change is constructed, and then in the direction of possible heat conduction and diffusion, the next area that may appear local overheating, i.e. the second-order overheating zone, is predicted and labeled. The purpose of using the third heat value is to determine the direction in which heat will spread in the future and how fast it will spread. The temperature gradient represents the speed and direction of temperature change in space, and the temperature gradient vector field is a vector field that describes the temperature change trend in space, representing the directional vector in each spatial block, representing the direction and size of heat flow; in specific implementation, the finite difference method can be used for calculation. The second-order overheating zone is used to lock the next possible position of abnormal temperature rise in advance, and to prepare for pre-control of the temperature of the target reactor.

[0051] Further, as a feasible implementation, the process of labeling the first heat conduction zone and the second heat conduction zone includes:

[0052] The process of starting the target reactor and the target heating furnace for the first time is set as a work cycle, the temperature rise rate threshold and the temperature upper limit threshold are set independently for each space block of the target reactor and the target heating furnace, and the temperature rise rate value and the temperature upper limit value of the target reactor and the target heating furnace are monitored in each work cycle; when the temperature rise rate value reaches the temperature rise rate threshold or the temperature upper limit value reaches the temperature upper limit threshold, it is determined that there is local overheating in the corresponding space block;

[0053] All the space blocks with local overheating in the target reactor are marked as the first heat conduction zone in a manner of marking after merging adjacent space blocks; all the space blocks with local overheating in the heating furnace are marked as the second heat conduction zone in a manner of marking after merging adjacent space blocks.

[0054] The work cycle is used to determine the time range for monitoring and judging, and in each work cycle, each space block of the reactor and the heating furnace is independently monitored and evaluated. The temperature rise rate threshold is used to detect the speed of temperature change, reflecting the dynamic characteristics of heat accumulation and transfer. The temperature upper limit threshold is used to detect whether the temperature reaches the highest safe temperature allowed by the equipment or process. The temperature rise rate threshold and the temperature upper limit threshold can be set according to historical data or experience in specific implementation; they are set independently for each space block, reflecting the differences in heat sensitivity and design parameters of different parts. In each work cycle, the temperature rise rate value of the space block is monitored in real time to determine whether it reaches or exceeds the corresponding threshold, and the temperature of the space block is monitored to determine whether it reaches or exceeds the corresponding temperature upper limit. As long as either condition is met, it is determined that the block has local overheating. This prevents both heat stress caused by too fast temperature rise and safety risks caused by high temperature exceeding the standard. All detected local overheating space blocks are merged based on spatial adjacency to avoid fragmented judgment. The merged area is more consistent with the continuity of heat accumulation and diffusion, which is beneficial to subsequent dynamic prediction and adjustment. Through periodic and spatial independent double judgment, the system's adaptability to complex thermal conditions of the reactor and the heating furnace is improved. At the same time, merging the overheating blocks avoids misjudgment caused by point-like abnormalities, improves the continuity and physical reasonableness of heat zone judgment, and is beneficial to the analysis of heat gradient and heat flow direction.

[0055] Further, as a feasible implementation, the content of the heat zone evaluation strategy includes:

[0056] The overheating space threshold is set, and a first heat conduction area whose heat energy value of the first heat conduction value reaches the overheating space threshold is marked as a first-order overheating area; the first heat conduction area and the second heat conduction area that exist in adjacent contact are merged in a manner of marking to set a to-be-detected overheating area; the first heat conduction value and the second heat conduction value are calculated in a weighted summation manner to obtain a merged heat energy value in the to-be-detected overheating area; when the merged heat energy value reaches the overheating space threshold, it is determined that the space blocks of the first heat conduction area and the second heat conduction area currently detected are overheating space blocks, and then it is determined that the to-be-detected overheating area is a first-order overheating area.

[0057] The overheating space threshold is used for secondary screening of the space region in the target reaction kettle, and the first-order overheating area is divided into two categories: the first category is a region where the first heat conduction area may abnormally heat up under the influence of the second heat conduction area, and the second category is a region where the first heat conduction area abnormally heats up due to the reaction of the target reaction kettle itself or other factors. The first heat conduction area and the second heat conduction area that exist in adjacent contact are merged in a manner of marking to set a to-be-detected overheating area, because if the distance is closer, the temperature loss in the heat medium conveying process is smaller, and the control accuracy of heating is higher, resulting in that the length or distance of the heat conduction medium system or pipeline of part of the reaction kettle and the heating furnace is relatively short, but in the case of maintaining a safe interval, it may have the effect of generating additional heat conduction heating, so in this embodiment, the first-order overheating area of the first category is set, and this case is considered. The overheating space threshold can be set according to historical data or experience in specific implementation. The heat energy values of the first heat conduction area and the second heat conduction area are synthesized into an overall heat energy index through weighted summation, and the weighting can reflect the different influence weights of the two parts of heat energy on overheating determination, and flexibly reflect the heat contribution of each region. The present embodiment upgrades from single-block heat energy determination to multi-block joint determination, which can be closer to the actual complex heat conduction coupling process; by introducing weighted summation, the heat influence of different regions (reaction kettle, heating furnace) can be differentiated, and the accurate identification of the first-order overheating area also provides stable and accurate basic data for subsequent dynamic heat energy trend analysis based on time step prediction and temperature gradient vector field.

[0058] In embodiment 2, the calculation process of the third heat conduction value includes:

[0059] Let T represent the real-time temperature value of the temperature field, and t represent the time step; let the first heat conduction value be represented as Q1, the second heat conduction value be represented as Q2, and the third heat conduction value be represented as Q3; let the average material density of the reaction kettle be represented as p, and let the constant-pressure specific heat capacity in the reaction kettle be c ρ ; let the ordinal number of the space block be i, and the volume size of the space block be V; let m represent the heat energy parameter,

[0060] The calculation formula of the third heat conduction value Q3 is: ,

[0061] wherein Q3 in the formula represents the third heat conduction value of the i-th spatial block (i) i (t+1) represents the real-time temperature value of the i-th spatial block at the t+1-th time step.

[0062] Since the spatial blocks are equally divided, the volume of each spatial block is represented as V. The average material density p of the reactor refers to the average mass per unit volume of the filled substance in the entire reactor itself and the internal space, i.e., the average mass concentration of the material per unit volume, which is used to represent the mass distribution of the entire reactor. The constant-pressure specific heat capacity in the reactor refers to the heat absorbed by unit mass of substance in the target reactor when the temperature is increased by 1 degree Celsius under constant pressure. In the formula, represents the theoretical heat energy value of the spatial block at the predicted real-time temperature value T i (t+1) . represents the weighted influence of the current heat conduction state on the future heat trend. The heat energy parameter m represents the degree of heat inertia, which considers the influence of the residual heat of the system at the previous time step on the temperature field change at the next time step, and can more accurately reflect the real trend in physical systems with slow heat conduction or heat hysteresis.

[0063] Further, as a feasible implementation manner, the process of obtaining the real-time temperature value T i (t +1) at the t+1-th time step includes:

[0064] obtaining the real-time temperature value T i t at the current time step of the target spatial block, monitoring and collecting the reactant flow value after the change of the reactant concentration and the stirring speed value of the target reactor; at the current time step, using the reactant flow value to calculate and generate a reactant heat load value, using the stirring speed value to calculate and generate a mechanical heat load value, updating the reactant heat load value and the mechanical heat load value to the real-time temperature value in the form of addition, and setting the updated real-time temperature value as the real-time temperature value T i (t+1) at the t+1-th time step.

[0065] The real-time temperature value T i t ​represents the actual measured temperature of the ith spatial block at the current time step t, represents the initial reference for temperature prediction. The reactant flow rate value represents the degree of reaction progress, which is a direct factor affecting the change of heat load; the stirring speed value represents the reaction stirring intensity of the target reactor, and the change of the intensity will change the heat convection rate and also introduce the energy consumption of mechanical heat load. In specific implementation, the reactant flow rate value and the stirring speed value of the target reactor after the change of reactant concentration can be monitored and collected using an online component analyzer. As a feasible implementation, the reactant heat load value is represented as Ta, the mechanical heat load value is represented as Tb, and the calculation formula of the updated real-time temperature value can be set as: T i (t +1) = T i t +Ta+Tb. Through the multi-source data fusion of multiple process variables, the embodiment can further improve the data accuracy.

[0066] In this embodiment, the process of calculating the temperature gradient vector field to generate the second-order superheating zone includes:

[0067] In each first-order superheating zone, a third heat conduction value matrix is constructed, and an initial gradient vector representing the heat transfer direction is calculated based on the third heat conduction value matrix; a fluid simulation rate and a vortex diffusion coefficient of the target reactor are generated using the CFD simulation flow field, and the initial gradient vector is corrected using the fluid simulation rate and the vortex diffusion coefficient to generate a corrected gradient vector;

[0068] The coordinates of the spatial blocks in each first-order superheating zone are marked as first-order block coordinates, and the integral processing of the heat flow path update is performed along the direction of the corrected gradient vector for each first-order block coordinate, and the numerical value after the integration is correspondingly represented as the second-order spatial coordinates of each spatial block completing the heat flow path update. The temperature field space region composed of each spatial block corresponding to the second-order spatial coordinates is marked as a second-order superheating zone.

[0069] A matrix is formed by the third thermal conductance values of each spatial block in the first-order superheat region, reflecting the thermal energy distribution state of the region. Based on the matrix, a gradient vector of the thermal energy spatial distribution is calculated, and the direction of the gradient vector represents the "natural" direction of heat flow, i.e., from the high thermal energy region to the low thermal energy region, embodying the basic direction of heat transfer. Through numerical simulation of the flow velocity field by CFD simulation, the fluid simulation rate and the eddy diffusion coefficient of the fluid in the reactor are obtained, the fluid simulation rate representing the flow velocity of the fluid at different times, and the eddy diffusion coefficient representing the ability of turbulent diffusion in the fluid, affecting the heat transfer efficiency in the fluid. The initial gradient vector is corrected by using the flow velocity and the eddy diffusion coefficient to adjust the heat conduction direction to reflect the influence of fluid flow on heat transfer, so that the gradient vector is more in line with the actual heat transfer path. The first-order block coordinate is the spatial position of each spatial block in the first-order superheat region. The integral of each block coordinate is performed along the direction of the corrected gradient vector to simulate the path and distance of heat flow along the direction; the integral result gives the new spatial coordinate, i.e., the second-order spatial coordinate, representing the spatial position of the potential heat flow after transmission, i.e., the downstream region of heat propagation. The integral along the direction of the corrected gradient vector represents the speed direction and intensity based on heat conduction, and the trajectory tracking of the future transmission path of heat in three-dimensional space. In specific applications, for example, the first-order block coordinate can be represented as P0, and the second-order spatial coordinate can be represented as P1. Then, in the time interval [t, t+Δt], the second-order spatial coordinate of the current spatial block can be represented as: wherein τ in the formula represents the time point, G(τ) in the formula represents the heat transfer correction gradient vector of the current spatial block at time τ, i.e., G(τ) in the formula is a vector function that changes with time, used to characterize the direction and intensity of heat transfer at the spatial point. The meaning of the second-order spatial coordinate can be represented as follows: according to the current heat conduction trend, heat will reach the next spatial block position; the position may initially have a normal temperature, but will soon overheat due to the concentration of heat flow. This embodiment dynamically estimates the future temperature rise region of the target reactor from the perspectives of both thermal power and fluid dynamics, improving the foresight and accuracy of the temperature control system.

[0070] Further, as a feasible implementation, the central difference method is used to calculate the initial gradient vector, and the process includes:

[0071] For each spatial block in the x, y, and z coordinate directions in the spatial coordinate system, the x gradient component, the y gradient component, and the z gradient component are calculated, and the difference between the third thermal conductance values of adjacent spatial blocks is denoted as the block temperature difference,

[0072] The calculation method of the x gradient component is to divide the block temperature difference in the x-axis direction by 2 times the step length in the x-axis direction.

[0073] The y gradient component is calculated by taking the temperature difference of the block in the y direction and dividing it by twice the step length in the y direction.

[0074] The z gradient component is calculated by taking the temperature difference of the block in the z direction and dividing it by twice the step length in the z direction.

[0075] The x gradient component, the y gradient component, and the z gradient component are combined to form an initial gradient vector.

[0076] The temperature gradient vector of each spatial block, i.e., the direction and rate of temperature change in three-dimensional space, is calculated for subsequent heat transfer path prediction and dynamic temperature control based on the gradient. The axial step length represents the distance between adjacent spatial blocks in the temperature field space. As a feasible implementation, in specific implementation, the central difference method is represented as:

[0077] The x gradient component is represented as: ,

[0078] The y gradient component is represented as: ,

[0079] The z gradient component is represented as: ,

[0080] The initial gradient vector is denoted as L and represented as: .

[0081] where Δx, Δy, Δz in the formula represent the step length of the spatial block in the corresponding coordinate axis direction, i.e., the distance between the center points of adjacent blocks. Compared with forward difference or backward difference, the central difference method has higher accuracy with second-order error, and is suitable for calculating the gradient under uniform grid. By calculating the gradient vector of each spatial block, the spatial heat flow direction can be accurately captured.

[0082] Further, the calculation process of the modified gradient vector includes:

[0083] Let the modified gradient vector be denoted as Yc, the initial gradient vector be denoted as Yo, the fluid simulation rate be denoted as ε, and the eddy diffusion coefficient be denoted as λ. The calculation formula of the modified gradient vector is: ,

[0084] where in the formula represents the vector differential of the fluid simulation rate, and represents the velocity curl.

[0085] The vector differential is the spatial derivative of the fluid velocity field, which quantifies the local velocity curl and direction of the fluid element, that is, the influence of the local flow field disturbance on the heat flow direction; the larger the vector differential value, the more intense the rotation of the fluid at that point. The vortex diffusion coefficient λ represents the parameter of the enhancement of local disturbance on heat diffusion. The larger the vortex diffusion coefficient λ value, the stronger the correction effect of the turbulent flow on the heat flow direction. The product of the vector differential and the vortex diffusion coefficient represents the weighted influence factor of the local flow rate disturbance on the heat flow migration direction. In the formula, Part represents the coefficient for correcting the initial gradient vector Yo. By calculating the modified gradient vector, the heat flow direction can be more accurately predicted when modeling the temperature field, which helps to identify potential second-order overheating areas in advance and avoid process out-of-control caused by uneven temperature distribution or local overheating.

[0086] Further, for the space block where the axial flow agitator of the target reactor is located, the axial step lengths of the x-axis, y-axis and z-axis are all taken as 2 times the radial length of the axial flow agitator; when the block temperature difference in the z-axis direction is more than twice the block temperature difference in the x-axis direction and the block temperature difference in the y-axis direction, numerical convergence is performed for the z-axis direction step length.

[0087] The axial flow agitator generates strong fluid disturbance and mixing by rotation, which may cause a sharp change in temperature distribution and gradient around it. The spatial step lengths in x, y and z directions are all set as 2 times the radial length of the axial flow agitator, indicating that the block size of spatial division is enlarged in this area, in order to match the physical size of the agitator and its influence scale on fluid flow and heat transfer, and to avoid the calculation complexity or error caused by too fine division. Taking twice the radial length of the agitator as the spatial step length makes the spatial division match the physical size of the equipment, which is beneficial to accurately capture the influence of the agitator on the temperature field. When the block temperature difference in the z-direction exceeds twice the block temperature difference in the x-direction and twice the block temperature difference in the y-direction, it indicates that the temperature change in the z-direction is very significant, and the heat flow changes strongly in the axial direction, so the spatial resolution in the z-axis direction needs to be improved. Therefore, the step length is adjusted in the z-axis direction, which can be applied as a smaller step length in specific implementation to improve the calculation accuracy until the gradient result is stable, ensuring that the simulation result is accurate and reliable.

[0088] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for dynamic heat transfer temperature control in a reactor heating furnace, characterized in that, The method includes: Step S1: Construct a temperature field in a spatial coordinate system, divide the spatial region of the temperature field into a number of spatial blocks along the coordinate axes, place the target reactor and the target heating furnace in the temperature field, mark the first heat conduction zone representing local overheating in the form of spatial blocks for the target reactor, and mark the second heat conduction zone representing local overheating in the form of spatial blocks for the target heating furnace. Step S2: Mark the size of the spatial block occupied by the first thermal conduction zone and the second thermal conduction zone along the spatial block in the temperature field, and mark the heat energy values ​​in the first thermal conduction zone and the second thermal conduction zone as the first thermal conduction value and the second thermal conduction value respectively, and construct a thermal zone evaluation strategy based on the first thermal conduction value and the second thermal conduction value. Step S3: Mark the superheated space blocks in the temperature field that indicate potential dynamic heat transfer in the first thermal conductivity zone using the thermal zone assessment strategy, and mark all superheated space blocks as first-order superheated zones; use the time step prediction method to predict and calculate the thermal energy trend value of each first-order superheated zone based on the first thermal conductivity value and the second thermal conductivity value, and mark it as the third thermal conductivity value. Step S4: Calculate the temperature gradient vector field of the corresponding local overheating zone using the third thermal conductivity value in each first-order overheating zone. Use the position pointed to by the temperature gradient vector field to generate a second-order overheating zone with the same spatial size as the first-order overheating zone and representing the end of potential dynamic heat transfer. Perform temperature overheating adjustment on the target reactor part covered by the second-order overheating zone. The process of marking the first and second thermal conductivity zones includes: The process of starting up the target reactor and the target heater is defined as one working cycle. The heating rate threshold and the upper temperature limit threshold are set independently for each spatial block of the target reactor and the target heater. The heating rate and the upper temperature limit of the target reactor and the target heater are monitored during each working cycle. When the heating rate reaches the heating rate threshold or the upper temperature limit reaches the upper temperature limit threshold, it is determined that there is local overheating in the corresponding spatial block. All the spaces within the target reactor that are locally overheated are labeled as the first heat conduction zone by merging adjacent spaces; all the spaces within the heating furnace that are locally overheated are labeled as the second heat conduction zone by merging adjacent spaces. The hot zone assessment strategy includes the following: Set an overheating space threshold. Mark the first thermally conductive area whose heat energy value reaches the overheating space threshold as a first-order overheating area. Mark the first and second thermally conductive areas that are in adjacent contact as adjacent space blocks and set them as the overheating area to be detected. Calculate the combined heat energy value in the overheating area to be detected by weighted summing of the first and second thermally conductive values. When the combined heat energy value reaches the overheating space threshold, determine that the space block of the currently detected first and second thermally conductive areas is an overheating space block, and then determine that the current overheating area to be detected is a first-order overheating area. The calculation process for the third thermal conductivity value includes: Let T represent the real-time temperature value of the temperature field, and t represent the time step; let the first thermal conductivity be denoted as Q1, the second thermal conductivity as Q2, and the third thermal conductivity as Q3; let the average material density of the reactor be denoted as ρ, and let the isobaric specific heat capacity inside the reactor be c. ρ Let the ordinal number of the spatial block be i, and the volume of the spatial block be V; let m represent the thermal energy parameter. The formula for calculating the third thermal conductivity value Q3 is as follows: , Wherein, Q3 (i) T represents the third thermal conductivity value Q3 of the i-th spatial block, where T is the thermal conductivity value Q3 of the i-th spatial block. i (t+1) It represents the real-time temperature value predicted by the i-th spatial block at time step t+1; The real-time temperature value T predicted at the (t+1)th time step i (t+1) The acquisition process includes: Obtain the real-time temperature value T of the target spatial block at the current time step. i t The system monitors and collects reactant flow rates and stirring speed values ​​of the target reactor after changes in reactant concentration. Within the current time step, it calculates reactant heat load using the reactant flow rate and mechanical heat load using the stirring speed. The reactant heat load and mechanical heat load values ​​are then added together to update the real-time temperature value. This updated real-time temperature value is set as the predicted real-time temperature T for the (t+1)th time step. i (t+1) .

2. The dynamic heat transfer temperature control method for a reactor heating furnace according to claim 1, characterized in that, The process of calculating the temperature gradient vector field to generate the second-order superheated region includes: In each first-order superheated region, a third thermal conductivity matrix is ​​constructed, and an initial gradient vector representing the heat transfer direction is calculated based on the third thermal conductivity matrix. The fluid simulation rate and eddy diffusion coefficient of the target reactor are generated using CFD simulation of the flow velocity field. The initial gradient vector is corrected using the fluid simulation rate and eddy diffusion coefficient and a modified gradient vector is generated. The coordinates of the spatial blocks in each first-order superheated region are labeled as first-order block coordinates. The first-order block coordinates are integrated along the direction of the modified gradient vector to represent the heat flow path update. The integrated values ​​are represented as the second-order spatial coordinates of each spatial block after the heat flow path update is completed. The temperature field spatial region composed of each spatial block corresponding to the second-order spatial coordinates is labeled as the second-order superheated region.

3. The dynamic heat transfer temperature control method for a reactor heating furnace according to claim 2, characterized in that, The initial gradient vector is calculated using the central difference method. This process includes: For each spatial block in the spatial coordinate system, calculate the x, y, and z gradient components respectively. Let the difference in the third thermal conductivity value between the block and the adjacent spatial blocks be represented as the block temperature difference. The x-gradient component is calculated by taking the block temperature difference in the x-axis direction and dividing it by twice the step size in the x-axis direction. The y-gradient component is calculated by taking the block temperature difference in the y-axis direction and dividing it by twice the step size in the y-axis direction. The z-gradient component is calculated by taking the block temperature difference in the z-axis direction and dividing it by twice the z-axis step size. The x-gradient components, y-gradient components, and z-gradient components are combined to form the initial gradient vector.

4. The dynamic heat transfer temperature control method for a reactor heating furnace according to claim 2, characterized in that, The calculation process of the corrected gradient vector includes: Let the corrected gradient vector be denoted as Yc, the initial gradient vector as Yo, the fluid simulation velocity as ε, and the eddy diffusion coefficient as λ. Then, the formula for calculating the corrected gradient vector is: , Where in the formula The vector derivative of the fluid simulation rate is represented by , and the velocity curl is represented by .

5. The dynamic heat transfer temperature control method for a reactor heating furnace according to claim 3, characterized in that, For the spatial block where the axial flow agitator of the target reactor is located, the axial step size of the x-axis, y-axis, and z-axis is twice the radial length of the axial flow agitator.

6. The dynamic heat transfer temperature control method for a reactor heating furnace according to claim 4, characterized in that, When the block temperature difference in the z-axis direction exceeds twice the block temperature difference in both the x-axis and y-axis directions, numerical convergence is performed with respect to the step size in the z-axis direction.

Images