Evaluation method for easy scattering degree of material cake and closed-loop control method for material bed crushing process

Abstract

The invention discloses a material cake scattering degree evaluation method and a material bed crushing process closed-loop control method, and belongs to the technical field of powder processing. The evaluation method comprises the following steps: carrying out a material bed extrusion experiment to obtain a material cake under different extrusion stresses, measuring the yield strength of the material cake, carrying out linear fitting on data points, and defining a slope as a yield coefficient k for quantitatively characterizing the easy scattering degree of the material cake. The closed-loop control method comprises the following steps: setting a k value target interval and a trend regression tolerance; and adjusting the final voltage when k exceeds the interval and does not meet the tolerance. The power consumption of a scattering section is taken as a main control target, the proportion of fine powder entering a roller is cooperatively controlled, a powder selecting or powder returning set value is defined as the rotating speed percentage of a powder selecting machine, a powder selecting loop and a final pressure loop are defined, a sequential control strategy of adjusting and selecting powder first and then adjusting pressure is adopted, and the stability criterion of Fin and act is set as that continuous two-time fluctuation is smaller than or equal to 1%. Quantitative evaluation and intelligent cooperative control of the easy-to-scatter property of the material cake are achieved, the scattering time is remarkably shortened, and the operation stability and the grinding efficiency are improved.

Description

Technical Field

[0001] This invention relates to powder processing technology in the fields of cement and mining, specifically to a method for evaluating the ease of dispersing material cakes and a closed-loop control method for the material bed crushing process. Background Technology

[0002] High-pressure bed milling technology (such as roller presses and vertical mills) is a highly efficient and energy-saving grinding method. Materials are crushed under the action of the bed milling equipment, and the crushed material is simultaneously compressed to form a dense bed. After passing through the compression zone, the compacted material is discharged in the form of a cake. The mechanical strength of the cake, especially its "ease of dispersal," is crucial to the system's operating efficiency and stability. An overly hard cake not only makes subsequent dispersal difficult but also indicates that the pressure exceeds the requirements for effective crushing, resulting in energy waste; a cake that is too loose indicates that the bed has not established effective interparticle forces, and energy cannot be efficiently transferred for particle crushing, leading to low crushing efficiency. Furthermore, engineering practice shows that materials under high pressure may experience localized shear failure, sliding towards areas of sudden pressure drop, causing the bed to collapse, which in turn causes vibration in bed milling equipment such as roller presses, affecting crushing efficiency.

[0003] Currently, there is a lack of quantitative evaluation indicators for the "ease of disintegration" of material cakes in industrial settings. Operators typically rely on experience to adjust parameters such as roller press pressure and circulating load, which results in problems such as adjustment lag and low energy efficiency. Therefore, there is an urgent need to develop an evaluation and control method that can scientifically quantify the ease of disintegration of material cakes and directly guide the optimization of production parameters to achieve stable and efficient operation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method that can quantitatively evaluate the degree of easy disintegration of the material cake and realize closed-loop control of process parameters based on the evaluation, so as to optimize the operation of the material bed crushing system.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for evaluating the ease of dispersing a material cake in a material bed crushing system, comprising the following steps: S1: Conduct a bed extrusion experiment on the target material to obtain at least two different preset extrusion stresses σ. press The ingredients are added; S2: Determine the yield strength σ of each cake obtained in step S1. yield ; S3: For multiple sets of data points (σ) press , σ yield A linear fit is performed, and the slope of the resulting straight line is defined as the yield coefficient k of the target material. The yield coefficient k is used to quantitatively characterize the ease with which the target material can be broken up after being crushed in the material bed. The higher the value of k, the less likely the material cake formed under the same conditions is to be broken up.

[0007] Preferably, the linear fitting in step S3 is a linear regression fitting without intercept.

[0008] Preferably, the ease with which the material cake can be broken up is verified by correlating the time T for the material cake to be completely broken up, and the yield coefficient k is positively correlated with the time T for the complete breaking up.

[0009] Preferably, the complete dispersal time T is defined as: under standard dispersal evaluation conditions, the cumulative undersize rate F of the cake. 0.08 (t) is the dispersing time required to reach the fine powder content corresponding to the intersection point of the fitting equation for the disintegration stage and the fitting equation for the grinding stage.

[0010] Secondly, the present invention provides a closed-loop control method for a bed pulverizing process based on the above-mentioned evaluation method, comprising the following steps: Step A1: Set the target control range for the yield coefficient k [k] min , k max ]; Step A2: Monitor the actual yield coefficient k of the material under the current process conditions in real time or periodically. act ; Step A3: When k act >k max If the trend regression tolerance condition is not met, an instruction to adjust the process parameters of the material bed crushing equipment will be generated. When k act <k min If the trend regression tolerance condition is not met, an instruction is generated to adjust the process parameters of the feedstock crushing equipment. The process parameters include the final pressure setting value P of the material bed crushing equipment. set ; The trend regression tolerance condition is defined as: k for three consecutive detection periods. act It exhibits a monotonically decreasing trend and the current value is related to k. max The deviation is less than 0.02, or for three consecutive detection cycles k act It shows a monotonically increasing trend and the current value is related to k. min The deviation is less than 0.02.

[0011] Preferably, the closed-loop control method further includes the following steps: Step A4: Set the mass percentage F of fine powder below the preset particle size in the material fed into the roller. in Target control range [F] min F max ]; Step A5: Real-time or periodic detection of the actual fine powder percentage F of the material currently feeding into the roller. in,act ; Adjusting process parameters includes coordinating the adjustment of the final pressure setpoint P. set and used to regulate F in,act The setting value S for selecting or returning powder. set So that k act With F in,act All of them approached and stabilized within their respective target control ranges; The powder selection or powder return setting value S set This refers to the relative rotational speed of the air classifier, expressed as a percentage of the rated speed. Its adjustable range is 20% to 80%, with an adjustment step of 5%. set Increasing the F value will increase the air classifier speed and improve the air classifier efficiency. in,act reduce; By adjusting S set To regulate F in,act The circuit is defined as the powder selection circuit, and is adjusted by P. set To regulate k act The circuit is defined as the final voltage circuit.

[0012] Furthermore, based on k act With F in,act Based on the detected values, adjustment instructions are generated according to the following rules: When k act >k max And F in,act >F max At that time, an up-regulation of S is generated. set and lower P set The instructions; When k act >k max And F in,act Located in [F min F max When [the P-value] is generated, it is down-regulated. set The instructions are given, and adjustments are made preferentially through the powder selection circuit; When k act <k min And F in,act <F min At that time, a down-regulation S is generated. set and raising P set The instructions; When k act <k min And F in,act Located in [F min F max When [this occurs], P is increased. setThe instructions are given, and the powder selection circuit is used for adjustment first.

[0013] Furthermore, the actual yield coefficient k is used to adjust... act The final pressure circuit is adjusted using a sequential control strategy. Within each control cycle, the powder selection circuit is adjusted first, followed by the F... in,act After stabilization, the power consumption E of the broken section is used as a guide. disp The degree of deviation determines whether to perform final pressure loop regulation.

[0014] Furthermore, the F in,act The criterion for stability is that the fluctuation is ≤1% for two consecutive tests.

[0015] Furthermore, the preset particle size is 80 μm.

[0016] Furthermore, the proportion F of fine powder in the material fed into the roller is determined through the following steps. in Target control range: Step B1: Prepare formulations with different fine powder mass ratios F in Samples of the same material series; Step B2: Under the same preset compressive stress, conduct bed extrusion tests on a series of samples and determine the yield strength σ of the resulting cake. yield ; Step B3: Draw σ yield With F in The changing curve, the curve exhibiting σ yield Value varies with F in Increase the trend of rising first and then falling; Step B4: Using the F corresponding to the peak value of the curve in The value is the median, and the preset fluctuation range is expanded to both sides to determine F. in The optimal control range.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are: 1. A brand-new quantitative index was proposed: the "yield coefficient k" was defined. This coefficient has a clear physical meaning (the sensitivity of the cake strength to the extrusion stress) and can directly and quantitatively characterize the ease with which the cake can be broken up, filling the gap in the existing technology that only has strength data but no evaluation standard.

[0018] 2. It bridges the gap between experimentation and production: It provides a complete methodology from laboratory testing (k-value acquisition) to on-site process evaluation and adjustment, enabling laboratory data to be directly used to guide production optimization.

[0019] 3. Revealed key process contradictions and achieved synergistic optimization control: Through systematic experiments, this invention, for the first time, clearly revealed the dual and opposing regulatory effects of the "feed fine powder ratio" on the "bulk structure strength" and "new fine powder generation efficiency" during high-pressure bed crushing. Based on this, the yield coefficient k, characterizing bulk cake strength, and the feed fine powder ratio were used as core coupled variables to construct a control mechanism with the power consumption E in the dispersing section as the key factor. disp As the main control target, with k and F in This is a dual-objective closed-loop control strategy with constrained variables. The strategy explicitly defines the setpoint S for either toner selection or toner return. set The physical definition and its relationship with F in The mapping relationship was defined, establishing the powder selection circuit and the final pressure circuit. A sequential control strategy of "adjusting the powder selection first, then adjusting the pressure" was adopted, and F was set. in,act Stability criteria (fluctuation ≤1% in two consecutive tests) and k-value trend regression tolerance criteria. The above method achieves synergistic optimization of final pressure and powder selection parameters, enabling the system to quickly converge to the comprehensive optimal working condition. It overcomes the limitations of traditional single-parameter adjustment, which cannot simultaneously consider the stability of the material bed and the crushing efficiency, and significantly improves the intelligence and economy of the system operation.

[0020] 4. Significant technical effects: By applying this invention, it is expected to reduce power consumption in the grinding section, reduce equipment vibration, improve system stability and grinding efficiency, and have significant energy-saving, consumption-reducing and quality-improving effects. Attached Figure Description

[0021] Figure 1 The flowchart below shows the overall process of evaluating and controlling the ease of dispersing material cakes according to an embodiment of the present invention.

[0022] Figure 2 The compressive stress σ of two different materials A and B press With yield strength σ yield The diagram illustrates the relationship, with slopes k and k respectively. A and k B .

[0023] Figure 3 For the feed fine powder ratio F in With the yield strength σ of the cake yield A diagram illustrating the relationship between the two.

[0024] Figure 4 This is a schematic diagram illustrating the positive correlation between the yield coefficient k and the time T for the cake to be completely broken up.

[0025] Figure 5 Preset pressure σ press With yield strength σ yield A diagram illustrating a direct proportional relationship Figure 6The proportion of fine powder fed to materials 6 and 7 is F. in With yield strength σ yield The diagram shows the relationship between materials, where (a) represents the test results of material 6 and (b) represents the test results of material 7. Detailed Implementation

[0026] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Figure 1 As shown, the overall solution provided by the present invention includes closed-loop control that evaluates the ease with which the material cake can be broken up through experiments and optimizes the process based on the evaluation results.

[0027] It should be noted that the present invention provides information for obtaining the extrusion stress σ. press and yield strength σ yield The specific experimental apparatus is not limited; any bed extrusion tester or similar apparatus capable of stably preparing the extruded material and testing its yield strength is suitable for this invention. The following examples are merely illustrations.

[0028] Example 1: Evaluation output and technical effect verification of easy breakage based on yield coefficient k To obtain reproducible evaluation results on easy dispersibility, a standardized method for verifying dispersibility effectiveness needs to be established. Experiments showed that ball mill grinding time per unit time has a good linear relationship with the increase in specific surface area and fine powder content of the material. When dispersing the material cake, the grinding and dispersing time in the ball mill also showed a good correlation with the increase in fine powder content during the dispersal process.

[0029] This embodiment uses a light media dispersing device with fixed parameters to perform standardized dispersing evaluation of the material cake. Specific parameters are as follows: the ball mill has a specification of Φ305mm×305mm, a rated power of 0.75kW, a rotation speed of 70r / min, and a rubber ball loading of approximately 2kg. A 500g sample of the material cake to be tested is placed in the ball mill. The ball mill is stopped after every 1 minute of operation, all material is removed, and sieved using a standard sieve. The cumulative sieve clearance rate of materials with a particle size less than 0.08mm is recorded and denoted as F. 0.08 (t). The total dispersing time generally does not exceed 20 minutes.

[0030] Cumulative screening rate F 0.08 The curve of (t) versus disintegration time t usually exhibits a two-segment characteristic: the first segment is the logarithmic growth stage of rapid disintegration of the cake, which can be fitted as F 0.08 (t)=p ln(t) +q; The second segment is the linear growth stage where the cake has basically disintegrated and is mainly undergoing grinding, which can be fitted as F 0.08 (t) = at + b. Since the increase in fine powder caused by the grinding action of the light media in the second section is very slow (usually less than 0.4% / min), its influence on judging whether the cake is "disintegrated" can be ignored.

[0031] The precise definition and determination method of the complete disintegration time T: The definition of "completely dispersed" state in this invention is based on the analysis of the physical mechanism of material particle size change during the dispersion process, and the "intersection method" is used as the criterion, as follows: 1. Process stage division: Cumulative screening rate F 0.08 (t) exhibits a clear two-stage characteristic as it changes over time: Disintegration Stage (Early Stage): This stage is dominated by the mechanical disintegration of the material cake agglomerates. 0.08 (t) increases rapidly with the dispersive time, exhibiting a non-linear growth, and can be fitted as a logarithmic function F. 0.08 (t)=p ln(t) +q.

[0032] Grinding stage (later stage): After the feed cake has been largely broken down, a dispersing device (such as a ball mill) applies a slight grinding action to the broken-down particles. 0.08 The growth of (t) mainly comes from newly generated fine powder, and its relationship with time is approximately linear, which can be fitted as: F 0.08 (t) = at + b.

[0033] 2. Physical meaning of "original fine powder content" b: The intercept b of the linear equation obtained by linearly fitting the experimental data of the grinding stage has a clear physical meaning. It represents the original fine powder content with a particle size of less than 0.08 mm that could be released by the complete disintegration of the material cake, assuming no grinding action. This value is a theoretical value obtained by back-deriving from the linear law of the grinding stage.

[0034] 3. Definition and calculation of the complete disintegration time T: Definition: The moment T when the material cake reaches the "completely broken up" state is the cumulative screening rate F during the disintegration stage. 0.08 (t) is the time required for the content of fine powder to increase to exactly equal to its theoretical "original fine powder content" b.

[0035] Calculation: By solving the equation formed by the fitting equation of the solution stage and the value of b, we obtain: p ln(t) + q = b This method avoids the subjectivity of manually setting a fixed threshold, making the "complete disintegration time" T an objective, reproducible, and accurate intrinsic indicator that characterizes the disintegration performance of the material cake.

[0036] Using the above method, the yield coefficient k and the time T for complete disintegration of different cement materials were tested to obtain the patches formed under the same conditions. The experimental results are as follows: Figure 4As shown, k and T are significantly positively correlated: the larger the k value, the larger the T value. If the material cake is divided into three groups—easy to break, moderately difficult to break—based on a threshold of k (e.g., using 0.20 and 0.28 as boundaries), the corresponding T value ranges for each group show significant differences. This proves that the yield coefficient k can serve as a reproducible and quantifiable evaluation index for the ease with which the material cake can be broken.

[0037] Example 2: Measurement and Comparison of k of materials fed into roller presses at different sites A bed crushing experiment was conducted on the raw materials fed into the roller presses from five different cement grinding sites (labeled as materials 1 to 5). For each material, five to eight different preset compressive stresses σ were applied. press Material cakes were prepared under stress conditions ranging from 50 to 200 MPa, with each stress point being tested three times. The yield strength σ of each material cake was then measured. yield .

[0038] For each material, the obtained (σ) press ,σ yield The data sets were fitted with non-intercept linear regression to obtain their respective high-pressure yield coefficients k1, k2, k3, k4, and k5, with a goodness of fit R0. 2 All values ​​are greater than 0.95, indicating that within the experimental pressure window, there is a good positive proportional relationship between extrusion pressure and cake strength. Figure 5 Figures (a)-(e) show the direct proportional relationship between materials 1 to 5. Figure 2 As shown in the principle, the k value for different materials is their σ. press -σ yield The slope of the relationship curve, the slope k of material A. A The slope k is greater than that of material B B This indicates that the cake formed by material A is more difficult to break up.

[0039] The comparison revealed ( Figure 5 (f) The k-values ​​of different materials vary significantly. Assuming that, based on historical operating experience, the reasonable range of k-values ​​for stable operation of this type of system is [0.20, 0.28], then in this measurement, only the k-values ​​of materials 1 and 3 fall within this range; the k-value of material 4 is too large, indicating that the resulting cake may be too hard and difficult to break up, requiring a reduction in the final pressure of the roller press or an adjustment of the feed particle size; the k-values ​​of materials 2 and 5 are too small, indicating that the cake may be too loose and insufficiently crushed, requiring an appropriate increase in pressure or optimization of the feed gradation.

[0040] This embodiment illustrates that by rapidly testing a new batch of material fed into the roller to obtain its k-value, the following can be achieved: 1) Set the economic final pressure: Based on the capacity of the on-site disintegration equipment, estimate the optimal operating pressure range; 2) Diagnostic changes in operating conditions: If the k-value of the same material deviates significantly from its normal range or the preset target range (e.g., abnormally low), it indicates an abnormal system operating condition. Based on experimental data statistics, an abnormally low k-value is related to the proportion of fine powder with a particle size less than 0.08 mm in the material fed into the roller (F... in A correlation exceeding 30% indicates a strong correlation. This finding can serve as an important basis for engineering diagnostics: when an abnormally low k-value is detected, the proportion of fine powder in the feed material should be checked and adjusted first (e.g., by improving powder selection efficiency, reducing circulating load, etc.). in (Controlling the pressure within an appropriate range) will quickly restore the system to stable operation, rather than blindly adjusting pressure parameters.

[0041] Example 3: The effect of the proportion of fine powder in the feed on k and process guidance Two typical feedstock materials (labeled as material 6 and material 7) were selected. Using an 80μm particle size cutoff, the materials were sieved into "fine powder" and "coarse particles." Different fine powder mass ratios (F0) were prepared by remixing. in A series of samples.

[0042] Under a fixed typical compressive stress (e.g., 114 MPa), the samples of each proportion were subjected to bed crushing and yield strength tests, and the results are as follows: Figure 3 and Figure 6 As shown. Specifically, Figure 6 (a) shows the yield strength σ of material 6. yield With F in The changing pattern, Figure 6 (b) illustrates the corresponding pattern for material 7. The yield strength σ of the two materials... yield (This reflects the relative magnitude of the k value under the same pressure) all vary with F in The increase in F shows a trend of first rising and then falling. in It reaches its peak around 20%. (For example...) Figure 3 As shown, there exists an optimal F. in The range ensures that the cake strength is moderate.

[0043] Analysis suggests that the above-mentioned patterns of change reflect a pair of mutually restrictive key factors in the bed pulverizing process: 1. Cake Strength Requirements: A certain amount of fine powder as filler helps to form a stable bed structure under pressure, enabling effective pressure transmission and thus obtaining appropriate cake strength (reasonable k-value). Too little fine powder results in a loose cake with insufficient strength.

[0044] 2. New fine powder generation efficiency (crushing effect): Excessive feeding of fine powder will have a "buffering effect" on the crushing of coarse particles in the feed bed, hindering the effective application of energy to particle crushing, resulting in a reduction in the amount of new fine powder generated and a decrease in crushing efficiency.

[0045] Therefore, the "optimal fine powder ratio range" referred to in this invention essentially aims to synergistically optimize the two mutually constraining objectives mentioned above: ensuring that the feed cake has moderate strength (facilitating pressure transmission and subsequent dispersal) while minimizing the negative impact on the efficiency of new fine powder generation, thereby achieving optimal system energy efficiency and crushing efficiency overall. This range is not a single peak point, but an optimized range that comprehensively considers the balance between strength and efficiency.

[0046] Based on this, this embodiment provides a method for determining the optimal range of fine powder content in the roller: through the experiment described in this embodiment, the yield strength (or k-value under the same pressure) of the material as a function of the fine powder content F is obtained. in The change curve (e.g.) Figure 6 (As shown). The optimal range can be determined based on the characteristics of the changing curve, for example, by assigning the F value corresponding to the peak intensity of the curve. in The value is taken as the midpoint of the interval, and a preset allowable fluctuation range (e.g., ±3% to ±8%) is extended to both sides of this midpoint to determine the F value used for actual control. in Target range. In actual production, the proportion of fine powder F in the feed material should be controlled through pre-crushing, efficient powder selection, and cyclic load adjustment. in Actively control the process within this target range. This can be combined with pressure regulation to achieve the dual goals of "moderate cake strength" and "efficient crushing." For example, when a high k value is detected and F... in When the F level is also too high, priority should be given to reducing the circulating load and improving the classifier efficiency to lower the F level. in It's about reducing stress, not just lowering it.

[0047] Example 4: Feasibility Example of Minimum Closed-Loop Control This embodiment provides a feasible minimum closed-loop example to illustrate how to utilize k and the proportion of fine powder entering the roller F. in Based on the test results, adjust the final pressure setpoint P accordingly. set With powder selection setting value S set This allows the power consumption of the system's dispersing section to operate within the target operating condition window, and offline verification demonstrates the improvement in the dispersibility of the material cake.

[0048] 4.1 Setting the Target Interval and Initial Conditions The main control objective is: unit power consumption of the disassembled section. Within the target range

[0049] The target state is: the proportion of fine powder entering the roller. (with 80μm as the boundary).

[0050] Criterion (Guardrail / Verification): The yield coefficient k is used for working condition identification, risk guardrail and control effect verification. In this embodiment, k act One of the following conditions must be met as a basis for steady-state maintenance: (1) fall into ; (2) It has not yet entered this interval, but it has shown a monotonically decreasing trend for three consecutive detection cycles and the current value is related to k. max The deviation is less than 0.02; (3) It has not yet entered this interval, but k has shown a monotonically increasing trend for three consecutive detection periods and the current value is similar to k. min The deviation is less than 0.02. It should be noted that this closed-loop control does not take "pulling k back to the target window" as the direct control objective. k is used to determine the direction of deviation from the operating condition and as a guardrail / verification criterion, and is not used as a hard condition to trigger voltage regulation alone.

[0051] Control quantity and limit: Final pressure setting value Adjustable range MPa; Adjust step size MPa.

[0052] Toner selection or toner return setting value S set： In this embodiment, S set Specifically, this corresponds to the relative speed of the air classifier, expressed as a percentage of the rated speed, with an adjustable range of 20% to 80% and an adjustment step of ΔS = 5%. set Increasing the speed of the classifier will improve its efficiency and reduce the proportion of fine powder in the material entering the roller.

[0053] General Logic Rules for Adjustment: This embodiment adopts a sequential adjustment strategy. Within each control cycle, the powder selection loop adjustment is executed first, followed by the adjustment of the powder selection loop. in,act After stabilization (fluctuation ≤1% in two consecutive tests), then according to E disp The deviation determines whether to perform final pressure loop regulation. There is a significant difference in the time constants of the two loops (response time of the powder selection loop < 4 min, response time of the final pressure loop > 10 min), and no coupled oscillations are generated in actual control.

[0054] Convergence Criterion: The closed-loop convergence condition is set as follows: after N consecutive closed-loop adjustment cycles (e.g., N = 3), the power consumption of the cake dispersing machine is [value missing]. Located between 0.51 and 0.73 kWh / t and Stable at Inside; at the same time As a guardrail and verification criterion, it must meet one of the following conditions: (1) in Within the range; (2) It has not yet entered this interval, but it has shown a monotonically decreasing trend for three consecutive detection cycles, and the current detection value is related to k. max The deviation is less than 0.02; (3) It has not yet entered this interval, but k has shown a monotonically increasing trend for three consecutive detection cycles, and the current value is related to k. min The deviation is less than 0.02. If the above conditions are met, the closed loop is considered to have converged, and the set value is maintained or the adjustment frequency is reduced.

[0055] Initial detection value: Power consumption of the dispersing section 1.21 kWh / t ; and This condition is classified as "high level of fine powder, difficult to disperse, and high tendency for the material cake to become dense".

[0056] 4.2 Closed-loop iterative control process Period 1 (j=1): Criterion: Power consumption of the broken section 1.21 kWh / t 0.73 kWh / t); (0.28) and (25%).

[0057] Control commands: 1. Classifying circuit (main circuit): Improves classifying efficiency, making... (Limited to) ), to reduce F in .

[0058] 2. Final pressure circuit: Lower the final pressure setpoint. , (Limited to) It is used to suppress the risk of excessive densification and alleviate the deviation of power consumption index in the dispersed section.

[0059] The power consumption of the dispersing section was obtained after the execution and retest. 0.92 kWh / t > 0.73 kWh / t , The indicators have improved but still do not meet the standards.

[0060] Period 2 (j=2): Criterion: Power consumption of the broken section =0.92 kWh / t > 0.73 kWh / t , .

[0061] Control commands: 1. Toner selection circuit: Continue to adjust upwards. (Limited).

[0062] 2. Final pressure circuit: The final pressure regulation decision for this cycle is as follows: Because the powder selection circuit has not yet reached its limit (current S) set,1 < 75%), and the excess power consumption has decreased from 0.48 kWh / t in cycle 1 to 0.19 kWh / t, therefore, the priority is to continue reducing F through the powder selection circuit. in To improve energy consumption indicators; Final pressure circuit maintains P set,2 = P set,1 (Not to be lowered for now), will be reassessed after the next cycle of retesting.

[0063] Post-execution retest: Power consumption of the dispersing section was 0.72 kWh / t. , All indicators have entered the target range.

[0064] Period 3 (j=3): Criterion: All indicators are within the target range.

[0065] Control commands: Hold commands: , .

[0066] The retest yielded the following results: power consumption of the dispersing section. =0.70 kWh / t, , If the conditions are met multiple times consecutively (3 times in this example), the closed loop is considered to have converged, and the setpoint is maintained or the adjustment frequency is reduced.

[0067] This illustrates that the output control rule of this invention is based on... and With the primary objective as the guiding principle, and under the risk barrier constraint of k, a sequential adjustment strategy of "adjusting powder selection first, then adjusting pressure" is adopted. This strategy can achieve the desired result within a few iterations. and Pull back to the target range, and use k as a guardrail / verification criterion for monitoring. A steady state is maintained by achieving the criterion of N consecutive compliances.

[0068] 4.3 Experimental Verification of Technical Effects To verify the actual improvement effect of the above closed-loop control strategy on the easy disintegration performance of the cake, a comparative experiment was conducted.

[0069] The same standard dispersive evaluation conditions as described in Example 1 (denoted as "Condition E") were used. Specifically, a laboratory ball mill with a diameter of 305mm × 305mm was used at a speed of 70 rpm, with approximately 2kg of rubber balls as the dispersive medium. A 500g sample of the test cake was taken for each dispersive test. After every 1 minute of operation, the mill was stopped and sieved, and the cumulative sieve clearance of materials with a particle size less than 0.08mm was recorded. .

[0070] For the initial operating conditions before closed-loop control (k=0.32, F...), respectively... in =30%, power consumption of the scattered section is 1.21 kWh / t) and the steady-state condition after closed-loop convergence (k=0.26, F in =22%, power consumption of the dispersing section is 0.70 kWh / t, which falls within the target range [0.51, 0.73] kWh / t). The cake sample prepared under these conditions was subjected to a dispersing test under "Condition E". The obtained... The data were calculated using the two-segment fitting method (i.e., logarithmic-linear fitting and intersection method) described in Example 1 to determine the corresponding time for complete scattering. .

[0071] The results show that after convergence... The time decreased from 10.51±0.4 min to 7.54±0.3 min (n=3), indicating that the power consumption in the dispersing section was the main control target, and the yield coefficient k and the proportion of fine powder entering the roller were the control factors. in Under a closed-loop control strategy with coordinated constraint variables, the system converged to the target power consumption range while significantly reducing the time for complete material disintegration by approximately 28%. This quantitatively confirms experimentally that adjusting process parameters... With F in By coordinating and regulating the control to the target range, the k criterion used for working condition verification falls into or returns to its target window, which can effectively improve the structure of the material cake and substantially enhance its dispersibility, thereby verifying the technical effect of the closed-loop control method of the present invention in terms of energy saving and efficiency improvement.

[0072] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0074] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for evaluating the ease of dispersing a material cake in a material bed crushing system, characterized in that, Includes the following steps: S1: Conduct a bed extrusion experiment on the target material to obtain at least two different preset extrusion stresses σ. press The ingredients are added; S2: Determine the yield strength σ of each cake obtained in step S1. yield ; S3: For multiple sets of data points (σ) press , σ yield A linear fit is performed, and the slope of the resulting straight line is defined as the yield coefficient k of the target material. The yield coefficient k is used to quantitatively characterize the ease with which the target material can be broken up after being crushed in the material bed. The higher the value of k, the less likely the material cake formed under the same conditions is to be broken up.

2. The method for evaluating the ease of breaking up the material cake according to claim 1, characterized in that, The linear fitting described in step S3 is a linear regression fitting without intercept.

3. The method for evaluating the ease of breaking up the material cake according to claim 1, characterized in that, The ease with which the material cake can be broken up is verified by correlating the time T for the material cake to be completely broken up, and the yield coefficient k is positively correlated with the time T for the complete breaking up.

4. A closed-loop control method for a bed pulverizing process based on the evaluation method described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step A1: Set the target control range for the yield coefficient k [k] min , k max ]; Step A2: Monitor the actual yield coefficient k of the material under the current process conditions in real time or periodically. act ; Step A3: When k act >k max If the trend regression tolerance condition is not met, an instruction to adjust the process parameters of the material bed crushing equipment will be generated. When k act <k min If the trend regression tolerance condition is not met, an instruction is generated to adjust the process parameters of the feedstock crushing equipment. The process parameters include the final pressure setting value P of the material bed crushing equipment. set ; The trend regression tolerance condition is defined as: k for three consecutive detection periods. act It shows a monotonically decreasing trend and the current value is related to k. max The deviation is less than 0.02, or for three consecutive detection cycles k act It shows a monotonically increasing trend and the current value is related to k. min The deviation is less than 0.

02.

5. The closed-loop control method according to claim 4, characterized in that, It also includes the following steps: Step A4: Set the mass percentage F of fine powder below the preset particle size in the material fed into the roller. in Target control range [F] min F max ]; Step A5: Real-time or periodic detection of the actual fine powder percentage F of the material currently feeding into the roller. in,act ; Adjusting process parameters includes coordinating the adjustment of the final pressure setpoint P. set and used to regulate F in,act The setting value S for selecting or returning powder. set So that k act With F in,act All of them approached and stabilized within their respective target control ranges; The powder selection or powder return setting value S set This refers to the relative rotational speed of the air classifier, expressed as a percentage of the rated speed. Its adjustable range is 20% to 80%, with an adjustment step of 5%. set Increasing the F value will increase the air classifier speed and improve the air classifier efficiency. in,act reduce; By adjusting S set To regulate F in,act The circuit is defined as the powder selection circuit, and is adjusted by P. set To adjust k act The circuit is defined as the final pressure circuit.

6. The closed-loop control method according to claim 5, characterized in that, Based on k act With F in,act Based on the detected values, adjustment instructions are generated according to the following rules: When k act >k max And F in,act >F max At that time, an up-regulation of S is generated. set and lower P set The instructions; When k act >k max And F in,act Located in [F min F max When [the P-value] is generated, it is down-regulated. set The instructions are given, and adjustments are made preferentially through the powder selection circuit; When k act <k min And F in,act <F min At that time, a down-regulation S is generated. set and raising P set The instructions; When k act <k min And F in,act Located in [F min F max When [this occurs], P is increased. set The instructions are given, and the powder selection circuit is used for adjustment first.

7. The closed-loop control method according to claim 6, characterized in that, Used to adjust the actual yield coefficient k act The final pressure circuit is adjusted using a sequential control strategy. Within each control cycle, the powder selection circuit is adjusted first, followed by the F... in,act After stabilization, the power consumption E of the broken section is used as a guide. disp The degree of deviation determines whether to perform final pressure loop regulation.

8. The closed-loop control method according to claim 7, characterized in that, The F in,act The criterion for stability is that the fluctuation is ≤1% for two consecutive tests.

9. The closed-loop control method according to any one of claims 6 to 8, characterized in that, The preset particle size is 80 μm.

10. The closed-loop control method according to any one of claims 5 to 8, characterized in that, The following steps are used to determine the fine powder ratio F of the material fed into the roller. in Target control range: Step B1: Prepare formulations with different fine powder mass ratios F in Samples of the same material series; Step B2: Under the same preset compressive stress, conduct bed extrusion tests on a series of samples and determine the yield strength σ of the resulting cake. yield ; Step B3: Draw σ yield With F in The changing curve, the curve exhibiting σ yield Value varies with F in Increase the trend of rising first and then falling; Step B4: Using the F corresponding to the peak value of the curve in The value is the median, and the preset fluctuation range is expanded to both sides to determine F. in The optimal control range.

Images