A method and system for monitoring a polymerization process

Abstract

The present application relates to the technical field of polymerization reaction monitoring, in particular to a monitoring method and system based on the polymerization reaction process, comprising: during the polymerization reaction, obtaining the in-situ refractive index distribution of the reaction liquid, the temperature gradient field of the polymerization reaction area and the vertical profile flow velocity vector of the fluid in the kettle through multiple spatial synchronous detection probes in the kettle; performing spatial difference operation on the in-situ refractive index distribution to demarcate the phase boundary of the reaction phase and the raw material phase; performing hotspot tracking on the temperature gradient field to locate the active polymerization core; calculating the flow field vorticity distribution using the flow velocity vector to identify the forced convection zone and the stagnant zone. The method can accurately monitor the polymerization reaction process and the mixing state of the material in the kettle, improve the stability of the polymerization reaction, and is suitable for monitoring the polymerization reaction in the preparation of polydextrose dietary fiber.

Description

Technical Field

[0001] This invention relates to the field of polymerization reaction monitoring technology, and in particular to a monitoring method and system based on polymerization reaction processes. Background Technology

[0002] In the preparation of polydextrose dietary fiber, the progress of the polymerization reaction directly determines key quality indicators such as product purity and molecular weight distribution. Therefore, accurate monitoring of the polymerization process is essential to ensure product quality. Current technologies for monitoring polydextrose polymerization reactions mostly employ traditional single-parameter detection methods. These methods can only collect basic parameters such as the overall temperature within the reaction vessel, the refractive index at a single monitoring point, or the macroscopic flow rate of the fluid within the vessel. Changes in these basic parameters are used to indirectly infer the progress of the polymerization reaction, failing to achieve precise capture and real-time feedback of changes in the microscopic state within the reaction system.

[0003] Existing monitoring methods have shortcomings: they struggle to accurately distinguish between the polymerized reaction phase and the incompletely polymerized feedstock phase, making it difficult to accurately grasp the actual progress of the polymerization reaction and easily leading to deviations in the judgment of the polymerization endpoint; relying solely on macroscopic flow velocity parameters cannot accurately determine the specific mixing state of the flow field within the reactor, nor can it effectively identify areas of thorough material mixing and stagnant areas of slow material exchange, thus making it difficult to detect problems such as incomplete polymerization and uneven material mixing. A polymerization reaction monitoring method is needed that can accurately capture the phase boundaries of the reaction system and clearly identify the mixing state of the flow field within the reactor, solving the problems of insufficient accuracy and inability to reflect microscopic changes within the reaction, and ensuring the stable and orderly progress of the polymerization reaction. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a monitoring method and system based on polymerization reaction processes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a monitoring method based on a polymerization reaction process, comprising:

[0006] During the polymerization reaction of polydextrose dietary fiber, real-time polymerization parameters are obtained from multiple spatial synchronous detection probes deployed inside the polymerization reactor. The real-time polymerization parameters include the in-situ refractive index distribution of the reaction liquid, the temperature gradient field of the polymerization reaction zone, and the flow velocity vector of the fluid in the reactor in the vertical cross-sectional direction.

[0007] Spatial difference calculation is performed on the in-situ refractive index distribution to identify the interface position where the refractive index changes abruptly in the reaction liquid, and the phase boundary between the polymerized reaction phase and the unpolymerized raw material phase is delineated based on the interface position.

[0008] Hotspot tracking is performed on the temperature gradient field of the polymerization reaction region to locate the spatial coordinates in the temperature gradient field where the gradient value exceeds a preset activation threshold, and the spatial coordinates are determined to be active polymerization cores.

[0009] Using the velocity vector of the fluid inside the reactor in the vertical cross-section, the vortex distribution of the flow field inside the polymerization reactor is calculated. Based on the vortex distribution, the forced convection zone where the material is well mixed and the stagnation zone where the material exchange is slow are identified.

[0010] As a further aspect of the present invention, spatial difference calculation is performed on the in-situ refractive index distribution to identify the interface positions in the reaction liquid where the refractive index undergoes a step change. Based on the interface positions, the phase boundary between the polymerized reaction phase and the unpolymerized feedstock phase is delineated, including:

[0011] The refractive index values ​​of all measurement points at the same time stamp are read from the multiple spatial synchronous detection probes to construct a three-dimensional spatial refractive index matrix.

[0012] The refractive index matrix in the three-dimensional space is calculated by difference along three orthogonal directions to obtain the rate of change of refractive index at each spatial point in the three directions;

[0013] Set a critical rate of change threshold, filter out spatial points where the rate of change of refractive index in three directions simultaneously exceeds the critical rate of change threshold, and mark the spatial points as refractive index transition points.

[0014] Using a spatial clustering algorithm, the refractive index transition points are clustered into a continuous spatial surface, which is the phase boundary;

[0015] The phase boundary divides the interior of the polymerization reactor into a reaction phase region with different physical properties, which has completed polymerization, and a raw material phase region that has not completed polymerization.

[0016] As a further aspect of the present invention, hotspot tracking is performed on the temperature gradient field of the polymerization reaction region to locate spatial coordinates in the temperature gradient field whose gradient values ​​exceed a preset activation threshold, and the spatial coordinates are determined to be active polymerization cores, including:

[0017] Spatial gradient calculation is performed on the temperature gradient field data of the polymerization reaction region to generate the temperature gradient amplitude of each spatial point;

[0018] The polymerization activation temperature gradient range corresponding to the polydextrose formulation is obtained from the historical database of polymerization reactions, and the lower limit of the activation temperature gradient range is used as the preset activation threshold.

[0019] Traverse all spatial points within the polymerization reactor, and filter out points whose temperature gradient amplitude is greater than the preset activation threshold to form a candidate hotspot set;

[0020] Connectivity analysis is performed on the candidate hotspot set to merge spatially adjacent candidate hotspots into a cluster of active aggregation reactions, and the geometric center of each cluster of active aggregation reactions is calculated.

[0021] The geometric center coordinates of each of the active clusters in the polymerization reaction are recorded as an active polymerization core.

[0022] As a further aspect of the present invention, the vortex distribution of the flow field inside the polymerization reactor is calculated using the velocity vector of the fluid in the vertical cross-section. Based on the vortex distribution, forced convection zones with sufficient material mixing and stagnation zones with slow material exchange are identified, including:

[0023] Based on the velocity vector of the fluid inside the vessel in the vertical cross-sectional direction, the vorticity scalar value of each grid cell in the three-dimensional flow field is calculated using the curl formula.

[0024] The calculated scalar values ​​of vorticity for all grid elements are normalized and mapped to a continuous numerical range from zero to one.

[0025] Set a high vorticity threshold and a low vorticity threshold. The region with a normalized vorticity scalar value greater than the high vorticity threshold is marked as the vortex core region, and the region with a normalized vorticity scalar value less than the low vorticity threshold is marked as the quiescent region.

[0026] The vortex core region is defined as the forced convection region due to the strong fluid rotation motion, and the stagnant region is defined as the stagnation region with slow material exchange due to the near-zero vortex volume.

[0027] As a further aspect of the present invention, the method further includes the step of evaluating the polymerization reaction process by integrating information from the phase boundary, the active polymerization core, the forced convection zone, and the retention zone:

[0028] The phase boundary, the coordinates of all the active polymerization cores, the spatial range of the forced convection zone, and the spatial range of the stagnation zone are registered into a unified three-dimensional spatial coordinate system of the polymerization reactor.

[0029] Calculate the shortest spatial distance from each of the active polymerization cores to the phase boundary, whereby the shortest spatial distance characterizes the proximity of the active polymerization core to the leading edge of the completed reaction region;

[0030] Analyze the flow field region properties of each active polymerization core to determine whether it is located in the forced convection zone or the stagnation zone;

[0031] Based on the shortest spatial distance from the active polymerization core to the phase boundary and the flow field region attributes in which it is located, a reaction propulsion potential weight is assigned to each active polymerization core, wherein active polymerization cores located in the forced convection region and close to the phase boundary receive a high reaction propulsion potential weight.

[0032] The sum of the reaction propulsion potential weights of all active polymerization cores is used as a quantitative indicator of the overall propulsion power of the polymerization reaction at the current moment.

[0033] As a further aspect of the present invention, the method further includes the step of generating a reaction regulation command sequence based on the reaction process evaluation results and real-time aggregation parameters:

[0034] A target range is set for the quantitative index of the overall propulsion force of the polymerization reaction;

[0035] The quantitative index of the overall propulsion power of the polymerization reaction, which is calculated in real time, is compared with the target range to determine whether it is lower than the lower limit of the range or higher than the upper limit of the range.

[0036] When the quantitative index is lower than the lower limit of the target range, select the specific core with the shortest distance to the phase boundary from the active polymerization cores located in the retention zone;

[0037] Generate a stirring paddle speed increase command designed to enhance fluid disturbance in the region where the specific core is located, the stirring paddle speed increase command including a target speed value and a duration;

[0038] When the quantitative index is higher than the upper limit of the target range, an instruction to increase the flow rate of the cooling medium in the jacket of the polymerization reactor is generated to suppress the reaction rate. The instruction to increase the flow rate of the cooling medium in the jacket of the polymerization reactor includes a target flow rate value and an action duration.

[0039] As a further aspect of the present invention, the method further includes the step of inverting the degree of aggregation distribution based on the time series evolution of the in-situ refractive index distribution:

[0040] The in-situ refractive index distribution data for multiple consecutive monitoring periods are acquired to form a refractive index spatiotemporal evolution data cube;

[0041] From the known correlation between the degree of polymerization and refractive index of polydextrose, the standard refractive index values ​​corresponding to different degrees of polymerization were extracted;

[0042] In the refractive index spatiotemporal evolution data cube, the trajectory of refractive index change over time is tracked at each spatial point;

[0043] By matching the refractive index change trajectory of each spatial point with the standard refractive index value, the evolution of the degree of polymerization of the material at the spatial point over time can be determined.

[0044] By synthesizing the evolution of the degree of polymerization over time at all spatial points within the polymerization reactor, a distribution map of products with different degrees of polymerization in three-dimensional space is constructed.

[0045] As a further aspect of the present invention, the method further includes the step of predicting the molecular weight distribution of the product based on the distribution spectrum of the degree of polymerization product:

[0046] From the above-mentioned correlation between the degree of polymerization of polydextrose and the refractive index standard, the average molecular weight corresponding to each degree of polymerization range is further obtained;

[0047] The distribution spectrum of the polymerization degree products is statistically analyzed, showing the proportion of the volume of materials in different polymerization degree ranges to the total volume of reactants.

[0048] The volume ratio of each degree of polymerization interval is multiplied by the average molecular weight corresponding to the degree of polymerization interval to obtain the contribution value of the degree of polymerization interval to the overall average molecular weight.

[0049] The contribution values ​​for all degree of polymerization ranges are summed to calculate the predicted overall average molecular weight of the product.

[0050] Based on the volume ratio distribution of different degree of polymerization ranges, a predicted product molecular weight dispersion index is generated.

[0051] As a further aspect of the present invention, the method further includes the step of performing targeted intervention on the retention area:

[0052] After the impeller speed increase command is activated according to the reaction control command sequence, the flow field changes due to the reaction control command sequence is continuously monitored.

[0053] In the new flow field after the speed increase, the vorticity distribution is recalculated to identify the updated forced convection region and stagnation region;

[0054] Determine whether the retention area where the specific core of the target is located has been eliminated or whether its range has been reduced;

[0055] If the stagnant zone is not eliminated, a fine-tuning command for the agitator tilt angle is further generated. The fine-tuning command for the agitator tilt angle is used to change the angle of attack of the agitator blades, thereby changing the extension direction of the main vortex and causing the forced convection zone to cover the original stagnant zone.

[0056] After the agitator tilt angle fine-tuning command is executed, the flow field change is monitored again until the target stagnation area is effectively eliminated or reduced to within the preset range.

[0057] As a further aspect of the present invention, the present invention also includes a monitoring system based on a polymerization reaction process, the system including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the computer program, implements the steps of the monitoring method based on a polymerization reaction process as described above.

[0058] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0059] Spatial difference calculations are performed on the in-situ refractive index distribution of the collected reaction liquid to identify the interface locations where the refractive index undergoes a step change. Based on these interface locations, the phase boundary between the polymerized reaction phase and the unpolymerized feedstock phase is delineated. This technology can accurately capture phase changes within the reaction system, clearly distinguish the specific boundaries between the reaction and feedstock phases, and overcome the limitations of conventional single-parameter monitoring in accurately locating phase boundaries. It allows for real-time monitoring of the actual progress of the polymerization reaction, avoiding deviations in the determination of the degree of polymerization due to the inability to distinguish phase states, thus making the monitoring of the polymerization reaction process more targeted and accurate.

[0060] By utilizing the velocity vector of the fluid within the reactor along its vertical profile, the vortex distribution of the flow field inside the polymerization reactor is calculated. Based on the vortex distribution, forced convection zones with thorough material mixing and stagnation zones with slow material exchange are identified. This technology enables in-depth analysis of the microscopic mixing state of the flow field within the reactor, accurately distinguishing the degree of material mixing in different regions. It overcomes the limitations of conventional macroscopic flow velocity monitoring, which cannot reflect the internal mixing differences of the flow field. It provides a clear understanding of the distribution and mixing status of materials within the reactor, preventing localized polymerization anomalies caused by uneven material mixing. This ensures that the polymerization reaction proceeds in a stable and uniform environment, improving the stability of the reaction process and the uniformity of product quality. Attached Figure Description

[0061] Figure 1 This is a flowchart of the monitoring method based on the polymerization reaction process described in this invention;

[0062] Figure 2 A flowchart for locating the active polymerization core;

[0063] Figure 3 Spatial distribution monitoring map of the initial stage of polydextrose polymerization reaction;

[0064] Figure 4 A spatiotemporal evolution diagram of refractive index in the polydextrose polymerization reaction;

[0065] Figure 5 This is a diagram illustrating the impact of increased impeller speed on the volume ratio of the flow field region. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0067] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0068] See Figure 1 This invention provides a monitoring method based on a polymerization reaction process. The overall implementation scheme is as follows: Multiple spatially synchronized detection probes are deployed inside the reactor. These probes can simultaneously acquire real-time polymerization parameters at different spatial points during the reaction. The acquired real-time polymerization parameters include the in-situ refractive index distribution of the reaction liquid, the temperature gradient field of the polymerization reaction zone, and the velocity vector of the fluid in the reactor along the vertical cross-section. Spatial difference calculations are performed on the acquired in-situ refractive index distribution to identify the interface locations where the refractive index undergoes a step change in the reaction liquid. Based on these interface locations, the phase boundary between the polymerized reaction phase and the unpolymerized raw material phase can be delineated. Hotspot tracking is performed on the acquired temperature gradient field of the polymerization reaction zone to locate the spatial coordinates where the gradient value exceeds a preset activation threshold. These spatial coordinates are identified as active polymerization cores. Simultaneously, using the acquired velocity vector of the fluid in the reactor along the vertical cross-section, the vortex distribution of the flow field inside the polymerization reactor is calculated. Based on this vortex distribution, forced convection zones with sufficient material mixing and stagnation zones with slow material exchange are identified.

[0069] In one embodiment of the present invention, refractive index values ​​of all measurement points at the same time stamp are read from multiple spatial synchronous detection probes to construct a three-dimensional spatial refractive index matrix. The three-dimensional spatial refractive index matrix is ​​then subjected to difference calculations along three orthogonal directions to obtain the rate of refractive index change for each spatial point in the three directions. A critical rate of change threshold is set, and spatial points whose refractive index change rates in all three directions simultaneously exceed the critical rate of change threshold are selected and marked as refractive index transition points. Using a spatial clustering algorithm, the refractive index transition points are aggregated into a continuous spatial surface, which serves as the phase boundary. This phase boundary divides the interior of the polymerization reactor into a reaction phase region with different physical properties (the reaction phase region has completed polymerization) and a raw material phase region (the raw material phase region has not completed polymerization).

[0070] In practice, the polymerization parameters, specifically the in-situ refractive index distribution of the reaction liquid, are obtained from multiple synchronous spatial probes deployed inside the polymerization reactor. These probes simultaneously measure the internal space of the reactor at the same time point, obtaining the refractive index value at each measurement point. During the middle stage of the polydextrose polymerization reaction, the refractive index values ​​exhibit a non-uniform spatial distribution, contrasting with the nearly uniform solution state at the initial stage of the reaction. After reading the refractive index values ​​from all spatial measurement points at the same time point, these values ​​are organized into a three-dimensional array according to the three-dimensional coordinates of the measurement points, thus constructing a three-dimensional spatial refractive index matrix that fully describes the spatial structure of the reaction system's optical properties at the current moment. The row, column, and layer indices of the three-dimensional spatial refractive index matrix correspond to the X, Y, and Z coordinates of the spatial points, respectively.

[0071] In some embodiments, spatial difference operations on the constructed three-dimensional refractive index matrix are crucial for identifying phase boundaries. The difference calculations are performed independently along the three orthogonal directions of the spatial rectangular coordinate system. For any non-boundary grid point within the three-dimensional refractive index matrix, the difference in refractive index values ​​between adjacent grid points in the positive and negative X directions is calculated, yielding the refractive index change component in the X direction. The same calculations are performed in the Y and Z directions. This central difference method yields the local refractive index change rate for each internal spatial point in the three directions. These change rates collectively constitute a three-dimensional refractive index change rate vector characterizing the rate and direction of spatial refractive index change at that point. In the polydextrose polymerization system, there is a significant difference in refractive index between the polymer phase that has undergone polymerization and the unreacted raw material monomer phase. This difference in physical properties leads to an abnormally high magnitude of the refractive index change rate vector in the local space near the two-phase interface. To quantitatively identify this interface, a critical change rate threshold needs to be set. This critical change rate threshold is a scalar value predetermined based on the physical properties of the polydextrose reaction system. The process iterates through all internal spatial points in the three-dimensional refractive index matrix, calculates the magnitude of the three-dimensional refractive index rate of change vector for each point, compares this magnitude with a critical rate of change threshold, and selects spatial points where the absolute values ​​of the magnitude components in the X, Y, and Z directions all exceed the critical rate of change threshold. In specific implementations, the three-dimensional refractive index rate of change vector is calculated... The formula is:

[0072]

[0073] Where R represents the refractive index of space, which is the optical refractive index at a point in the space grid. The indices representing the coordinates of the three-dimensional spatial grid correspond to the coordinates in space. , , direction; Specifically, this is represented in spatial grid coordinates as The refractive index value at that location; Indicates at point The calculated three-dimensional spatial rate of change of refractive index vector is a three-dimensional vector composed of three components, each of which has its spatial derivative approximated using the central difference method.

[0074] First component: , indicating that the refractive index is Direction (corresponding index) The rate of change of ).

[0075] The second component: , indicating that the refractive index is Direction (corresponding index) The rate of change of ).

[0076] The third component: , indicating that the refractive index is Direction (corresponding index) The rate of change of ).

[0077] Spatial points that meet the screening criteria mean that their refractive index has changed drastically in space. These spatial points are marked as refractive index transition points. In the early stages of the polymerization reaction, refractive index transition points may be sparsely and discretely distributed in space. As the reaction proceeds, the number of refractive index transition points will gradually increase and connect into sheets.

[0078] Optionally, after identifying all refractive index transition points, these discrete sets of spatial points need to be transformed into a continuous surface description. Since the real phase interface is a continuous surface, the discrete refractive index transition points can be considered as samples of this surface. Spatial clustering algorithms, such as density-based clustering methods, are used to process all refractive index transition points. The spatial clustering algorithm groups nearby refractive index transition points into the same cluster based on their spatial distance, with each cluster representing a continuous potential phase interface segment. It can be understood that for a clear, fully developed phase boundary, all refractive index transition points are typically clustered into a large cluster. The spatial clustering algorithm aggregates these refractive index transition points into a continuous spatial surface. This spatial surface constructed by the algorithm represents the phase boundary between the polymerized reaction phase and the unpolymerized feedstock phase. The phase boundary is a closed or open surface that divides the three-dimensional space inside the polymerization reactor into two distinct regions. In some embodiments, the inner side of the phase boundary typically corresponds to a region with a higher refractive index, i.e., the reaction phase region where polymerization has been completed, while the outer side of the phase boundary corresponds to a region with a lower refractive index, i.e., the raw material phase region where polymerization has not been completed. This division is based on the physical law that the refractive index of the product increases during polydextrose polymerization. The morphology, area, and position of the phase boundary in three-dimensional space evolve over time, directly reflecting the advancement of the polymerization front.

[0079] In one embodiment of the present invention, see [reference] Figure 2 Spatial gradient calculations are performed on the temperature gradient field data of the polymerization reaction region to generate the temperature gradient amplitude at each spatial point. The polymerization activation temperature gradient range corresponding to the polydextrose formulation is obtained from the historical database of polymerization reactions, and the lower limit of this activation temperature gradient range is used as the preset activation threshold. All spatial points within the polymerization reactor are traversed, and points with temperature gradient amplitudes greater than the preset activation threshold are selected to form a candidate hotspot set. Connectivity analysis is performed on the candidate hotspot set, and spatially adjacent candidate hotspots are merged into an active polymerization cluster. The geometric center of each active polymerization cluster is calculated. The coordinates of the geometric center of each active polymerization cluster are recorded as an active polymerization core.

[0080] Based on the velocity vector of the fluid inside the vessel along the vertical cross-section, the scalar value of vorticity for each grid cell in the three-dimensional flow field is calculated using the curl formula. The calculated scalar values ​​of vorticity for all grid cells are normalized and mapped to a continuous numerical range from zero to one. High and low vorticity thresholds are set. Regions with normalized vorticity values ​​greater than the high vorticity threshold are marked as vortex core regions, and regions with normalized vorticity values ​​less than the low vorticity threshold are marked as stagnant regions. Vortex core regions are defined as forced convection regions due to intense fluid rotation, while stagnant regions are defined as stagnation regions with near-zero vorticity due to slow material exchange.

[0081] In practical implementation, during the polydextrose polymerization reaction, there are temperature differences at different spatial points inside the reactor. A spatial synchronous detection probe simultaneously measures the temperature distribution data, i.e., the temperature gradient field data. Spatial gradient calculation is performed on the temperature gradient field data. For a discrete temperature measurement lattice, by calculating the temperature difference between adjacent points in three spatial directions for each internal point, the temperature change vector at that point can be obtained. The magnitude of the temperature change vector is the temperature gradient amplitude at that spatial point. The temperature gradient amplitude characterizes the degree of temperature change at that point in space. In practical implementation, the polydextrose polymerization reaction is an exothermic process, and the active polymerization core is usually accompanied by rapid local temperature changes. Therefore, the high-temperature gradient amplitude region may be associated with the most active reaction point. In some embodiments, obtaining the polymerization activation temperature gradient range corresponding to the polydextrose formulation from a historical database of polymerization reactions is a key step in setting the threshold. The historical database stores typical temperature gradient amplitude ranges recorded during known active reaction stages under the same or similar formulations, stirring, and heating conditions. The polymerization activation temperature gradient range is an empirical numerical range, and its lower limit represents the minimum local temperature change intensity required to initiate and maintain the polymerization reaction. The lower limit of the polymerization activation temperature gradient range is used as the preset activation threshold, which is a scalar value used for screening. The point set consisting of all spatial points within the polymerization reactor is traversed, and the calculated temperature gradient amplitude for each spatial point is compared with the preset activation threshold. Points with temperature gradient amplitudes greater than the preset activation threshold are selected, forming a candidate hotspot set. The points in the candidate hotspot set may be spatially dispersed or clustered in local areas.

[0082] Optionally, connectivity analysis of the candidate hotspot set involves associating discrete high-temperature gradient points as the core of a continuous reaction region. Connectivity analysis is based on the principle of spatial proximity, setting a connectivity distance criterion. For example, if the spatial Euclidean distance between two candidate hotspots is less than a certain set value, the two hotspots are considered adjacent. Based on this criterion, the candidate hotspot set is traversed, and spatially adjacent candidate hotspots are merged into the same group, forming a cluster of reactive hotspots. A cluster of reactive hotspots may contain several or even dozens of candidate hotspots, and its spatial morphology reflects the extent of the local reactive region. The geometric center of each cluster is calculated; the coordinates of the geometric center can be obtained by taking the arithmetic mean of the spatial coordinates of all candidate hotspots within the cluster. It can be understood that the geometric center coordinates of each cluster are recorded as an active reactive core, and the location of the active reactive core characterizes the center of the local reactive region.

[0083] In practical implementation, the velocity vector is a three-dimensional vector describing the magnitude and direction of the fluid velocity at each point along the vertical profile. Based on these discrete velocity vector data, the discrete curl formula from computational fluid dynamics is used to calculate the scalar value of vorticity for each grid cell in the three-dimensional flow field. Vorticity is a vector, and its scalar value (i.e., vorticity intensity) characterizes the intensity of the rotation of fluid particles. The calculated scalar value of vorticity varies greatly at different locations within the reactor. Near the tip of the agitator blades and in the center of the main vortex, the scalar value of vorticity is usually high, while in the corners of the reactor wall or in areas far from the agitator, the scalar value of vorticity is low. The scalar value of vorticity calculated from all grid cells is normalized. The purpose of normalization is to linearly map all values ​​to a continuous numerical range from zero to one, making data from different batches or at different times comparable. One method of normalization is to find the maximum and minimum values ​​of vorticity scalar value in the current flow field, and then map each original vorticity value to the [0,1] interval using a linear transformation formula.

[0084] In some embodiments, setting high vorticity and low vorticity thresholds is a key step in distinguishing flow field structures. These thresholds are predefined constants between 0 and 1, with the high vorticity threshold being greater than the low vorticity threshold. All grid cells are traversed, and the normalized vorticity scalar value of each cell is compared to these two thresholds. Regions with normalized vorticity scalar values ​​greater than the high vorticity threshold are marked as vortex core regions, corresponding to the core region of the flow field where fluid rotation is most intense. Regions with normalized vorticity scalar values ​​less than the low vorticity threshold are marked as stagnant regions, corresponding to regions where the fluid is almost still or only has slow advection. Due to the intense fluid rotation, vortex core regions promote rapid material mixing and mass transfer, and are therefore defined as forced convection regions with well-mixed materials. Stagnant regions, with near-zero vorticity and slow fluid exchange, are prone to localized material accumulation and uneven reactions, and are therefore defined as stagnation regions with slow material exchange. The spatial distribution of the forced convection zone and the stagnation zone directly reflects the difference in mixing efficiency within the polymerization reactor. This can be understood as the scalar value of vorticity. The normalization formula is:

[0085]

[0086] in: Represents the original vorticity scalar value of a certain grid cell. This represents the maximum value of the original vorticity scalar value of all grid elements in the current flow field. This represents the minimum original vorticity scalar value of all grid elements in the current flow field. This represents the normalized vorticity scalar value of the grid cell.

[0087] In one embodiment of the invention, the phase boundary, the coordinates of all active polymerization cores, the spatial range of the forced convection zone, and the spatial range of the stagnation zone are registered in a unified three-dimensional spatial coordinate system of the polymerization reactor. The shortest spatial distance from each active polymerization core to the phase boundary is calculated, which characterizes the proximity of the active polymerization core to the leading edge of the completed reaction region. The flow field region attributes of each active polymerization core are analyzed to determine whether it is located in the forced convection zone or the stagnation zone. Based on the shortest spatial distance from the active polymerization core to the phase boundary and the flow field region attributes, a reaction propulsion potential weight is assigned to each active polymerization core, with active polymerization cores located in the forced convection zone and close to the phase boundary receiving higher reaction propulsion potential weights. The sum of the reaction propulsion potential weights of all active polymerization cores is calculated as a quantitative indicator of the overall propulsion power of the polymerization reaction at the current moment.

[0088] A target range is set for the quantitative index of the overall propulsion power of the polymerization reaction. The quantitative index of the overall propulsion power of the polymerization reaction, calculated in real time, is compared with the target range to determine whether it is below the lower limit or above the upper limit. When the quantitative index is below the lower limit of the target range, a specific core with the shortest distance to the phase boundary is selected from the active polymerization cores located in the stagnation zone. A stirrer speed increase command is generated to enhance the fluid disturbance in the region where the specific core is located. The stirrer speed increase command includes a target speed value and a duration. When the quantitative index is above the upper limit of the target range, a command is generated to increase the flow rate of the cooling medium in the polymerization reactor jacket to suppress the reaction rate. The flow rate increase command includes a target flow rate value and an action duration.

[0089] In practice, the phase boundary, the coordinates of all active polymerization cores, the spatial range descriptions of the forced convection zone and the stagnation zone are all registered into a unified three-dimensional coordinate system of the polymerization reactor. The registration process involves spatial coordinate transformation and alignment to ensure all spatial elements are within the same metric framework, enabling accurate spatial relationship calculations. The shortest spatial distance from each active polymerization core to the phase boundary is calculated in three-dimensional space. For each active polymerization core coordinate point, the distances to all points on the spatial surface representing the phase boundary are calculated, and the minimum value is taken. This shortest spatial distance characterizes the proximity of the active polymerization core to the leading edge of the completed reaction region; the shorter the distance, the closer the active polymerization core is to the leading edge boundary of the reaction phase. The flow field region attributes of each active polymerization core are analyzed to determine whether it is located in the forced convection zone or the stagnation zone. The determination is based on whether the three-dimensional coordinates of the active polymerization core fall within the polygon describing the spatial range of the forced convection zone. If it is, it is determined to be located in the forced convection zone; otherwise, it is further checked whether it falls within the spatial range description of the stagnation zone to determine whether it is located in the stagnation zone.

[0090] In some embodiments, a reaction propulsion potential weight is assigned to each active polymerization core based on the shortest spatial distance from the active polymerization core to the phase boundary and the properties of the flow field region where the active polymerization core is located. The allocation rule is based on a physical mechanism: active polymerization cores located in the forced convection zone receive more sufficient feedstock and heat diffusion, thus exhibiting higher reaction propulsion potential at the same distance from the phase boundary compared to active polymerization cores located in the stagnation zone; simultaneously, the closer an active polymerization core is to the phase boundary, the easier it is for its reaction products to integrate into the formed reaction phase, and the higher its potential to propel the reaction front. Based on this, active polymerization cores located in the forced convection zone and close to the phase boundary receive a high reaction propulsion potential weight, while active polymerization cores located in the stagnation zone and far from the phase boundary are assigned a low reaction propulsion potential weight. It can be understood that the reaction propulsion potential weight... This can be quantified using a function related to distance and region attributes; one possible representation is as follows:

[0091]

[0092] in: This represents the shortest spatial distance from the active polymerization nucleus to the phase boundary. It is a small constant that avoids a denominator of zero. It is a coefficient related to the properties of the flow field region. It is a normalization coefficient. It is the sum of the reaction propulsion potential weights of all active polymerization cores at the current moment. This sum is used as a quantitative indicator of the overall propulsion power of the polymerization reaction at the current moment. The higher the value of this indicator, the more active sites with high propulsion potential are in the reaction system and the more active they are.

[0093] Optionally, a target range is set for the overall propulsion dynamics quantification index of the polymerization reaction. This target range is a preset numerical range, with its upper and lower limits determined based on the desired polymerization rate and product quality control targets. During reaction monitoring, the real-time calculated overall propulsion dynamics quantification index is compared with the preset target range to determine whether it is below the lower limit or above the upper limit. When the real-time overall propulsion dynamics quantification index is below the lower limit, it indicates insufficient overall propulsion dynamics, requiring activation of the stagnant reaction region. From the active polymerization cores located in the stagnant zone, a specific core with the shortest distance to the phase boundary is selected. This specific core is considered the most likely key point in the stagnant zone to be activated to propel the reaction. A stirrer speed increase command is generated to enhance fluid disturbance in the region where the specific core is located. The stirrer speed increase command includes a target speed value and a duration. The target speed value is higher than the current stirrer speed, and the duration specifies the length of time the stirrer operates at the target speed. By increasing the stirring intensity, the static state of the flow field in the stagnant zone is broken, promoting material mixing and mass transfer. When the real-time overall polymerization reaction propulsion quantification index exceeds the upper limit of the target range, it indicates that the overall reaction is progressing too rapidly, potentially posing a risk of localized overheating or reaction runaway, necessitating rate suppression. A command to increase the cooling medium flow rate in the polymerization reactor jacket is generated to suppress the reaction rate. This command includes a target flow rate value and an application duration. The target flow rate value is higher than the current cooling medium flow rate, and the application duration specifies the duration of operation at the target flow rate. By enhancing heat transfer, the temperature of the reaction system is reduced, thereby slowing down the polymerization reaction rate.

[0094] See Figure 3 This is a spatial distribution monitoring map of the initial stage of polydextrose polymerization, visually presenting the distribution relationship between phase boundaries and active polymerization nuclei within the reactor. Phase boundaries represent the interface between the polymerized reaction phase and the unpolymerized feedstock phase, exhibiting a wavy undulation that reflects the non-uniform propagation of the reaction front. Active nuclei in the forced convection zone represent highly mixed, efficient mass and heat transfer regions, serving as the primary driving force for the polymerization reaction. They are numerous and widely distributed on both sides of the phase boundaries, with some nuclei adhering closely to the boundaries, indicating a greater potential contribution to the reaction front. Active nuclei in the stagnant zone represent inert regions with slow material exchange and static flow, exhibiting weak reaction propagation potential and serving as a key target for subsequent control. They are fewer in number and mostly concentrated far from phase boundaries or in dead zones, forming a clear spatial differentiation from the active nuclei in the forced convection zone.

[0095] In one embodiment of the present invention, in-situ refractive index distribution data for multiple consecutive monitoring periods are acquired to form a refractive index spatiotemporal evolution data cube. Standard refractive index values ​​corresponding to different degrees of polymerization are extracted from the known correlation between the degree of polymerization and refractive index of polydextrose. The refractive index change trajectory of each spatial point over time is tracked within the refractive index spatiotemporal evolution data cube. The refractive index change trajectory of each spatial point is matched with the standard refractive index value to determine the evolution of the degree of polymerization of the material at that spatial point over time. By combining the evolution of the degree of polymerization over time at all spatial points within the polymerization reactor, a distribution map of products with different degrees of polymerization in three-dimensional space is constructed. The average molecular weight corresponding to each degree of polymerization interval is further obtained from the correlation between the degree of polymerization and refractive index of polydextrose. The proportion of the material volume in different degree of polymerization intervals to the total volume of the reactants in the distribution map of the degree of polymerization products is statistically analyzed. The volume proportion of each degree of polymerization interval is multiplied by the average molecular weight corresponding to that degree of polymerization interval to obtain the contribution value of that degree of polymerization interval to the overall average molecular weight. The contribution values ​​of all degree of polymerization intervals are summed to calculate the predicted overall average molecular weight of the product. Based on the volume ratio distribution of different degree of polymerization ranges, a predicted product molecular weight dispersion index is generated.

[0096] In practical implementation, in-situ refractive index distribution data for multiple consecutive monitoring cycles are acquired. Each monitoring cycle generates a three-dimensional spatial refractive index matrix as described in the above embodiment. These three-dimensional matrices, arranged in chronological order, are stacked in the time dimension to form a four-dimensional refractive index spatiotemporal evolution data cube. This cube contains information in three spatial dimensions and one temporal dimension, recording the history of refractive index changes at each point within the reactor over time. Standard refractive index values ​​corresponding to different degrees of polymerization are extracted from the known standard correlation between the degree of polymerization and refractive index of polydextrose. This correlation is established through a database or function relationship based on previous calibration experiments, clarifying the deterministic correspondence between the degree of polymerization of the polydextrose product and the refractive index of its solution. Within the refractive index spatiotemporal evolution data cube, the trajectory of refractive index change at each spatial point over time is tracked. For a specific point with spatial coordinates (i,j,k), its refractive index change trajectory is a one-dimensional curve showing the change of refractive index value over a time monitoring cycle sequence. The refractive index change trajectory of each spatial point is matched with the standard refractive index value extracted from the standard correlation between the degree of polymerization and refractive index of polydextrose. The matching process is achieved by finding the standard refractive index value range to which the refractive index value belongs, thereby determining the evolution of the degree of polymerization of the material at that spatial point over time, that is, when the material at that point reached what degree of polymerization.

[0097] In some embodiments, by comprehensively analyzing the evolution of the degree of polymerization over time at all spatial points within the polymerization reactor, a distribution map of products with different degrees of polymerization can be constructed in three-dimensional space. This distribution map is a three-dimensional spatial field, where each spatial location is assigned a scalar representing the current degree of polymerization. The map visually displays the spatial distribution of high-degree-of-polymerization products and low-degree-of-polymerization products within the reactor at a specific moment. From the correlation between the degree of polymerization and refractive index of polydextrose, the average molecular weight corresponding to each degree-of-polymerization interval is further obtained. Polydextrose is a polymer, and its molecular weight is proportional to its degree of polymerization; each degree-of-polymerization interval corresponds to an average molecular weight value. The proportion of material volume within different degree-of-polymerization intervals to the total volume of reactants in the distribution map of degree-of-polymerization products is calculated by dividing the sum of the volumes of grid cells whose values ​​fall within each degree-of-polymerization interval into the total volume. The relationship between degree-of-polymerization intervals, corresponding refractive index ranges, and average molecular weight can be understood by referring to a table in the following form:

[0098] Table 1: Comparison of Polydextrose Degree Range, Refractive Index Range, and Average Molecular Weight

[0099] 1-10 1.3300-1.3350 180-1620 11-20 1.3351-1.3400 1782-3240 21-30 1.3401-1.3450 3402-4860 31-40 1.3451-1.3500 5022-6480

[0100] Optionally, the volume ratio of each degree of polymerization interval is multiplied by the average molecular weight corresponding to that degree of polymerization interval to obtain the contribution value of that degree of polymerization interval to the overall average molecular weight. The contribution values ​​of all degree of polymerization intervals are summed to calculate the predicted overall average molecular weight of the product. The calculation can be expressed as:

[0101]

[0102] in: This represents the total number of aggregation degree intervals. It is a range index. Representing the The proportion of the volume of material in each degree of polymerization range to the total volume of reactants. Representing the The average molecular weight corresponding to each degree of polymerization range This refers to the calculated overall average molecular weight of the predicted product. Based on the volume proportion distribution across different degree of polymerization ranges, a predicted product molecular weight dispersion index is generated. This index characterizes the width of the product molecular weight distribution. A common calculation method is the molecular weight distribution coefficient, defined as the ratio of the predicted overall average molecular weight to the number average molecular weight. The number average molecular weight can be obtained using a similar weighting method but with a different averaging approach. In some embodiments, the distribution map of the degree-of-polymerization product and the resulting predicted molecular weight distribution parameters provide a quantitative basis for assessing product homogeneity from the perspective of spatial composition distribution. By comparing the distribution maps of the degree-of-polymerization product at different reaction stages or under different process conditions, the evolution of spatial homogeneity in the reaction process can be analyzed.

[0103] See Figure 4 This is a spatiotemporal evolution analysis chart of the refractive index during the polymerization of polydextrose, showing the trend of refractive index change over time at five different spatial points during the polymerization process. The refractive index is directly related to the degree of polymerization of polydextrose and can be used to invert the reaction progress and product distribution. The refractive index at all spatial points increases monotonically with reaction time, indicating that the polymerization reaction continues and the average degree of polymerization of the material continuously increases. The curve shows an approximately linear growth, indicating that the reaction rate remains relatively stable within the monitoring period. At the initial moment, the refractive indices at each point are concentrated between 1.328 and 1.332, with minimal differences, indicating good material homogeneity at the start of the reaction. At the final moment, the refractive indices at each point show significant differentiation, expanding to a range of 1.375 to 1.418, reflecting a significant increase in spatial heterogeneity during the reaction process. The refractive index is positively correlated with the degree of polymerization of polydextrose, and the time series of refractive indices at each point can be converted into the evolution history of the degree of polymerization through a standard comparison relationship.

[0104] In one embodiment of the present invention, after a stirrer speed increase command is initiated according to a reaction control command sequence, the flow field changes due to the command is continuously monitored. In the new flow field after the speed increase, the vorticity distribution is recalculated, and the updated forced convection zone and stagnation zone are identified. It is determined whether the stagnation zone where the target specific core was originally located has been eliminated or whether its range has been reduced. If the stagnation zone has not been eliminated, a stirrer tilt angle fine-tuning command is further generated. The stirrer tilt angle fine-tuning command is used to change the angle of attack of the stirrer blades to change the extension direction of the mainstream vortex, causing the forced convection zone to cover the original stagnation zone. After the stirrer tilt angle fine-tuning command is executed, the flow field changes are monitored again until the target stagnation zone is effectively eliminated or reduced to within a preset range.

[0105] In practical implementation, targeted intervention is carried out in the stagnation zone. When the stirring speed increase command is initiated according to the reaction control command sequence, the control system of the polymerization reactor executes the target speed value and duration, and the stirring impeller operates at a higher speed. During and after the execution of the stirring speed increase command, a spatial synchronous detection probe continuously monitors the flow field changes due to the stirring speed increase command, and obtains updated velocity vector data of the fluid in the reactor in the vertical cross-section. In the new flow field after the speed increase, the vorticity distribution is recalculated. Based on the updated velocity vector data, the vorticity scalar value of each grid cell in the three-dimensional flow field is calculated using the same curl formula as in the previous embodiment, and all vorticity scalar values ​​are normalized. Based on the preset high vorticity judgment threshold and low vorticity judgment threshold, the updated forced convection zone and stagnation zone are identified. Compared with the flow field structure before the speed increase, the spatial range of the forced convection zone may expand due to enhanced stirring, and the intensity of the vortex core zone may also increase, while the spatial range of some of the original stagnation zones may shrink or disappear.

[0106] In some embodiments, determining whether the stagnation zone where the target specific core was originally located has been eliminated or its range has been reduced is crucial for evaluating the effectiveness of the speed increase command. The target specific core is the specific core with the shortest distance to the phase boundary selected from the active polymerizing cores located in the stagnation zone when the impeller speed increase command is generated. Under the new flow field structure, it is checked whether the three-dimensional coordinates of the target specific core are still within the updated identified stagnation zone space. If the coordinates of the target specific core are no longer within any stagnation zone, it is determined that the stagnation zone where the target specific core was originally located has been eliminated. If the coordinates of the target specific core are still within a certain stagnation zone, the spatial volume of this stagnation zone is further calculated and compared with the spatial volume of the stagnation zone before the impeller speed increase command was executed. If the volume has decreased, it is determined that the range has been reduced. If the stagnation zone has not been eliminated and its spatial volume has not decreased to the expected extent, it indicates that simply increasing the impeller speed has failed to achieve effective intervention in the target stagnation zone.

[0107] Optionally, if the stagnant zone where the target core is located is not effectively eliminated, a fine-tuning command for the impeller tilt angle is further generated. This command changes the angle of attack of the impeller blades. An impeller typically consists of a drive shaft and one or more blades mounted on it. The blade angle of attack refers to the angle between the blade plane and the plane of rotation. Changing the blade angle of attack alters the direction of the force exerted by the blades on the fluid, thereby changing the extension direction and shape of the main vortex. The fine-tuning command includes a target tilt angle value, which is an angle. The control system drives the impeller's adjustment mechanism to adjust the blade angle of attack to the target value. By adjusting the blade angle of attack, the vortex generated by the forced convection zone can be guided to extend into previously inaccessible stagnant zones, causing the forced convection zone to cover or disperse the original stagnant zone, thus enhancing material exchange in that area. After the agitator tilt angle fine-tuning command is executed, the flow field changes need to be monitored again. The spatial synchronous probe continues to collect flow velocity data and recalculates the vortex distribution, identifying the forced convection zone and stagnation zone to determine whether the target stagnation zone has been effectively eliminated or reduced to within the preset range. The preset range is a volume threshold or spatial size threshold set according to process requirements. It can be understood that directional intervention is an iterative process; if a tilt angle adjustment fails to achieve the target, a new adjustment command can be generated based on a new flow field analysis. The impact of agitator tilt angle fine-tuning on the direction of the mainstream vortex can be described by fluid dynamics relationships, such as the adjusted mainstream vortex axis direction vector. Compared with the direction vector before adjustment and angle of attack change There exists a functional relationship, which can be simplified as follows:

[0108]

[0109] in: It is a rotation about a specific axis The rotation matrix of the angle. It is the direction vector of the main vortex axis before adjustment. It is the change in angle of attack set by the agitator tilt angle fine-tuning command. It is the predicted adjusted direction vector of the mainstream vortex axis. In some embodiments, the process of continuously monitoring, recalculating, judging and generating instructions is repeated until the target stagnation zone is effectively eliminated or its spatial range is reduced to within a preset range, thereby achieving precise and active control of the inefficient mixing area in the reactor and ensuring the uniformity of the polymerization reaction.

[0110] See Figure 5This is a graph analyzing the impact of increased impeller speed on the volume percentage of the flow field regions. It visually demonstrates the changes in the volume percentage of the three types of flow field regions within the polymerization reactor before and after the increase in impeller speed, serving as a core basis for evaluating the effectiveness of flow field control. The forced convection zone significantly expands, with its volume percentage jumping from 45% to 65%, an increase of 44.4%. This indicates that after the increase in stirring intensity, the area within the reactor where materials are thoroughly mixed and where mass and heat transfer are highly efficient has greatly expanded, providing a better kinetic environment for the polymerization reaction. The stagnation zone shrinks significantly, with its volume percentage decreasing from 35% to 15%, a reduction of 57.1%. This demonstrates that the increase in impeller speed effectively broke the original static state of the flow field, significantly eliminating the inert region with slow material exchange, which is the core achievement of this control measure. The transition zone remains stable, with its volume percentage consistently maintained at 20%. As a buffer zone between the forced convection zone and the stagnation zone, its stability indicates that the flow field changes mainly occur between the core active zone and the inert zone, without causing drastic disturbances to the overall flow field structure.

[0111] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A monitoring method based on a polymerization reaction process, characterized in that, A polymerization reactor used in the preparation of polydextrose dietary fiber, the method comprising: During the polymerization reaction of polydextrose dietary fiber, real-time polymerization parameters are obtained from multiple spatial synchronous detection probes deployed inside the polymerization reactor. The real-time polymerization parameters include the in-situ refractive index distribution of the reaction liquid, the temperature gradient field of the polymerization reaction zone, and the flow velocity vector of the fluid in the reactor in the vertical cross-sectional direction. Spatial difference calculation is performed on the in-situ refractive index distribution to identify the interface position where the refractive index changes abruptly in the reaction liquid, and the phase boundary between the polymerized reaction phase and the unpolymerized raw material phase is delineated based on the interface position. Hotspot tracking is performed on the temperature gradient field of the polymerization reaction region to locate the spatial coordinates in the temperature gradient field where the gradient value exceeds a preset activation threshold, and the spatial coordinates are determined to be active polymerization cores. Using the velocity vector of the fluid inside the reactor in the vertical cross-section, the vortex distribution of the flow field inside the polymerization reactor is calculated, and the forced convection zone with sufficient material mixing and the stagnation zone with slow material exchange are identified based on the vortex distribution. Spatial difference calculations are performed on the in-situ refractive index distribution to identify the interface locations where the refractive index undergoes a step change in the reaction liquid. Based on these interface locations, the phase boundary between the polymerized reaction phase and the unpolymerized feedstock phase is delineated, including: The refractive index values ​​of all measurement points at the same time stamp are read from the multiple spatial synchronous detection probes to construct a three-dimensional spatial refractive index matrix. The refractive index matrix in the three-dimensional space is calculated by difference along three orthogonal directions to obtain the rate of change of refractive index at each spatial point in the three directions; Set a critical rate of change threshold, filter out spatial points where the rate of change of refractive index in three directions simultaneously exceeds the critical rate of change threshold, and mark the spatial points as refractive index transition points. Using a spatial clustering algorithm, the refractive index transition points are clustered into a continuous spatial surface, which is the phase boundary; The phase boundary divides the interior of the polymerization reactor into a reaction phase region that has completed polymerization and a raw material phase region that has not completed polymerization, both of which have different physical properties. Hotspot tracking is performed on the temperature gradient field of the polymerization reaction region to locate spatial coordinates in the temperature gradient field whose gradient values ​​exceed a preset activation threshold. These spatial coordinates are then identified as active polymerization cores. Spatial gradient calculation is performed on the temperature gradient field data of the polymerization reaction region to generate the temperature gradient amplitude of each spatial point; The polymerization activation temperature gradient range corresponding to the polydextrose formulation is obtained from the historical database of polymerization reactions, and the lower limit of the activation temperature gradient range is used as the preset activation threshold. Traverse all spatial points within the polymerization reactor, and filter out points whose temperature gradient amplitude is greater than the preset activation threshold to form a candidate hotspot set; Connectivity analysis is performed on the candidate hotspot set to merge spatially adjacent candidate hotspots into a cluster of active aggregation reactions, and the geometric center of each cluster of active aggregation reactions is calculated. The geometric center coordinates of each of the active polymerization clusters are recorded as an active polymerization core; Using the velocity vector of the fluid inside the reactor in the vertical cross-section, the vortex distribution of the flow field inside the polymerization reactor is calculated. Based on the vortex distribution, forced convection zones with thorough material mixing and stagnation zones with slow material exchange are identified, including: Based on the velocity vector of the fluid inside the vessel in the vertical cross-sectional direction, the vorticity scalar value of each grid cell in the three-dimensional flow field is calculated using the curl formula. The calculated scalar values ​​of vorticity for all grid elements are normalized and mapped to a continuous numerical range from zero to one. Set a high vorticity threshold and a low vorticity threshold. The region with a normalized vorticity scalar value greater than the high vorticity threshold is marked as the vortex core region, and the region with a normalized vorticity scalar value less than the low vorticity threshold is marked as the quiescent region. The vortex core region is defined as the forced convection region due to the strong fluid rotation motion, and the stagnant region is defined as the stagnation region with slow material exchange due to the near-zero vortex volume.

2. The monitoring method based on polymerization reaction process according to claim 1, characterized in that, The method further includes a step of evaluating the polymerization reaction progress by integrating information from the phase boundary, the active polymerization core, and the forced convection zone and retention zone: The phase boundary, the coordinates of all the active polymerization cores, the spatial range of the forced convection zone, and the spatial range of the stagnation zone are registered into a unified three-dimensional spatial coordinate system of the polymerization reactor. Calculate the shortest spatial distance from each of the active polymerization cores to the phase boundary, whereby the shortest spatial distance characterizes the proximity of the active polymerization core to the leading edge of the completed reaction region; Analyze the flow field region properties of each active polymerization core to determine whether it is located in the forced convection zone or the stagnation zone; Based on the shortest spatial distance from the active polymerization core to the phase boundary and the flow field region attributes in which it is located, a reaction propulsion potential weight is assigned to each active polymerization core, wherein active polymerization cores located in the forced convection region and close to the phase boundary receive a high reaction propulsion potential weight. The sum of the reaction propulsion potential weights of all active polymerization cores is used as a quantitative indicator of the overall propulsion power of the polymerization reaction at the current moment.

3. The monitoring method based on the polymerization reaction process according to claim 2, characterized in that, The method further includes the step of generating a reaction regulation instruction sequence based on the reaction process evaluation results and real-time aggregation parameters: A target range is set for the quantitative index of the overall propulsion force of the polymerization reaction; The quantitative index of the overall propulsion power of the polymerization reaction, which is calculated in real time, is compared with the target range to determine whether it is lower than the lower limit of the range or higher than the upper limit of the range. When the quantitative index is lower than the lower limit of the target range, select the specific core with the shortest distance to the phase boundary from the active polymerization cores located in the retention zone; Generate a stirring paddle speed increase command designed to enhance fluid disturbance in the region where the specific core is located, the stirring paddle speed increase command including a target speed value and a duration; When the quantitative index is higher than the upper limit of the target range, an instruction to increase the flow rate of the cooling medium in the jacket of the polymerization reactor is generated to suppress the reaction rate. The instruction to increase the flow rate of the cooling medium in the jacket of the polymerization reactor includes a target flow rate value and an action duration.

4. The monitoring method based on the polymerization reaction process according to claim 3, characterized in that, The method further includes the step of inverting the degree of aggregation distribution based on the time series evolution of the in-situ refractive index distribution: The in-situ refractive index distribution data for multiple consecutive monitoring periods are acquired to form a refractive index spatiotemporal evolution data cube; From the known correlation between the degree of polymerization and refractive index of polydextrose, the standard refractive index values ​​corresponding to different degrees of polymerization were extracted; In the refractive index spatiotemporal evolution data cube, the trajectory of refractive index change over time is tracked at each spatial point; By matching the refractive index change trajectory of each spatial point with the standard refractive index value, the evolution of the degree of polymerization of the material at the spatial point over time can be determined. By synthesizing the evolution of the degree of polymerization over time at all spatial points within the polymerization reactor, a distribution map of products with different degrees of polymerization in three-dimensional space is constructed.

5. The monitoring method based on the polymerization reaction process according to claim 4, characterized in that, The method further includes the step of predicting the molecular weight distribution of the product based on the distribution spectrum of the degree of polymerization product: From the above-mentioned correlation between the degree of polymerization of polydextrose and the refractive index standard, the average molecular weight corresponding to each degree of polymerization range is further obtained; The distribution spectrum of the polymerization degree products is statistically analyzed, showing the proportion of the volume of materials in different polymerization degree ranges to the total volume of reactants. The volume ratio of each degree of polymerization interval is multiplied by the average molecular weight corresponding to the degree of polymerization interval to obtain the contribution value of the degree of polymerization interval to the overall average molecular weight. The contribution values ​​for all degree of polymerization ranges are summed to calculate the predicted overall average molecular weight of the product. Based on the volume ratio distribution of different degree of polymerization ranges, a predicted product molecular weight dispersion index is generated.

6. The monitoring method based on the polymerization reaction process according to claim 5, characterized in that, The method further includes the step of implementing targeted intervention in the retention area: After the impeller speed increase command is activated according to the reaction control command sequence, the flow field changes due to the reaction control command sequence is continuously monitored. In the new flow field after the speed increase, the vorticity distribution is recalculated to identify the updated forced convection region and stagnation region; Determine whether the retention area containing the specific core of the target has been eliminated or its range has been reduced; If the stagnant zone is not eliminated, a fine-tuning command for the agitator tilt angle is further generated. The fine-tuning command for the agitator tilt angle is used to change the angle of attack of the agitator blades, thereby changing the extension direction of the main vortex and causing the forced convection zone to cover the original stagnant zone. After the agitator tilt angle fine-tuning command is executed, the flow field change is monitored again until the target stagnation area is effectively eliminated or reduced to within the preset range.

7. A monitoring system based on a polymerization reaction process, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the monitoring method based on polymerization reaction process as described in any one of claims 1 to 6.

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