Method for resource utilization of household garbage incineration fly ash

Abstract

The present application relates to waste incineration resource utilization technical field, especially to a kind of household garbage incineration fly ash resource utilization method, comprising: fly ash raw ash is treated by detoxification water washing, control moisture content is at 30~35%;Fly ash raw material is mixed with first aggregate and powder, real-time detection conveying motor current signal, based on current transient peak number and standard deviation and energy consumption correction factor calculation clumping index;Premix material is ground, with first aggregate as grinding medium, based on clumping index and moisture content adjustment grinding time and speed, detect the particle size value of mixed material, and according to actual energy consumption and particle size value correction energy consumption correction factor is used for subsequent batch;Finally, mixed material is mixed and stirred with second aggregate, third aggregate and water, to obtain road inorganic binder, and water addition is determined according to particle size value.The present application realizes the self-adaptive regulation and control of fly ash physical properties, improves product quality stability and energy efficiency.

Description

Technical Field

[0001] This invention relates to the field of waste resource utilization technology, and in particular to a method for the resource utilization of fly ash from municipal solid waste incineration. Background Technology

[0002] Fly ash from municipal solid waste incineration is a hazardous waste generated during the incineration process, containing harmful substances such as heavy metals and dioxins. Its safe disposal and resource utilization are important issues in the field of solid waste management. Currently, the main technical routes for fly ash resource utilization include landfill after solidification and stabilization treatment, use as raw material for co-processing in cement kilns, and preparation of building materials after high-temperature sintering or melting, or a combination of low-temperature pyrolysis and water washing desalination processes. Among these, using fly ash for road engineering material production after low-temperature pyrolysis and water washing desalination processes is considered a promising approach. Related technologies mainly include detoxifying and desalinizing fly ash through a combination of low-temperature pyrolysis and water washing desalination processes, and mixing the detoxified and desalinated fly ash with cement, lime, and other cementitious materials to prepare roadbed materials. Existing technologies typically use fixed process parameters for fly ash treatment, such as directly mixing it with other aggregates after water washing detoxification, or using it after mechanical grinding to improve particle characteristics. While these methods have achieved the resource utilization of fly ash to some extent, they generally lack an adaptive adjustment mechanism for fluctuations in the physical properties of detoxified and desalinated fly ash raw materials, making it difficult to guarantee the stability of the production process and the uniformity of product quality.

[0003] In practical engineering applications, it has been found that due to differences in the combined process of low-temperature pyrolysis and water washing desalination of municipal solid waste incineration fly ash and the equipment used, the physical properties of the detoxified and desalinated fly ash raw materials vary significantly. In particular, fluctuations in moisture content and agglomeration directly affect the treatment effect of subsequent processes. Existing technologies often use the same process parameters when processing different batches of detoxified and desalinated fly ash raw materials. This leads to problems such as insufficient grinding and uneven mixing when fly ash agglomeration is severe or moisture content is high, affecting the performance stability of the final product. Furthermore, the fixed-parameter operation mode makes it difficult to achieve optimized energy consumption control, resulting in energy waste. In addition, existing technologies lack in-depth analysis of the correlation between the characteristics of detoxified and desalinated fly ash and process parameters, making it impossible to establish an effective feedback adjustment mechanism, thus restricting the economy and reliability of the resource recovery process.

[0004] Chinese Patent Publication No. CN111393045A discloses a method for preparing cementitious materials from waste incineration fly ash, comprising the following steps: Step 1, preparing plant straw fermentation liquid; Step 2, degrading dioxins and heavy metals in fly ash; Step 3, modifying plant fibers; Step 4, preparing cementitious materials. It is evident that the method for preparing cementitious materials from waste incineration fly ash has the following problems: the physical properties of detoxified and desalinated fly ash raw materials vary significantly. When processing different batches of detoxified and desalinated fly ash raw materials, using the same process parameters can lead to problems such as insufficient grinding and uneven mixing when the fly ash agglomerates severely or has a high moisture content, affecting the performance stability of the final product. Summary of the Invention

[0005] Therefore, this invention provides a method for the resource utilization of fly ash from municipal solid waste incineration, in order to overcome the problems of unstable product quality and high energy consumption caused by fluctuations in the physical properties of fly ash in the prior art.

[0006] To achieve the above objectives, the present invention provides a method for the resource utilization of fly ash from municipal solid waste incineration, comprising:

[0007] Step S1: Detoxify and wash the raw fly ash to obtain fly ash raw material with a moisture content controlled within a first preset range;

[0008] Step S2: The fly ash raw material is fed into a mixing device through a metering and conveying device and mixed with the first aggregate and powder to obtain a premixed material;

[0009] Among them, the current signal of the drive motor of the metering and conveying device is detected in real time during the process of conveying the fly ash raw material. Based on the current signal and the energy consumption correction factor, the agglomeration index characterizing the degree of fly ash agglomeration is calculated. The current signal includes the number of instantaneous peak currents and the standard deviation of current.

[0010] Step S3: The premixed material is fed into the grinding equipment through a metering and conveying device, and the first aggregate is used as the grinding medium to crush and grind the premixed material to obtain a mixed material.

[0011] Specifically, based on the agglomeration index and the moisture content, the grinding intensity parameters of the grinding equipment are adjusted, including grinding time and grinding speed; the energy consumption correction factor is corrected according to the actual unit mass energy consumption of the grinding equipment and the product particle size qualification rate, and applied to the production of subsequent batches;

[0012] Step S4: Mix the mixture, the second aggregate, the third aggregate, and water in a mixing device to obtain an inorganic binder product for road use.

[0013] The amount of water added during mixing is determined based on the actual particle size of the mixture.

[0014] Further, step S2 includes:

[0015] Step S21: Record the number of times the instantaneous peak value of the current signal of the drive motor of the conveying device is greater than the first current threshold during the process of conveying a unit mass of the fly ash raw material, and obtain the number of instantaneous peak values ​​of the current.

[0016] Step S22: Calculate the standard deviation of the current based on the current value of the drive motor of the conveying device during the conveying of a unit mass of the fly ash raw material;

[0017] Step S23: Determine the basic value of the agglomeration index based on the number of instantaneous peak currents and the standard deviation of the current;

[0018] Step S24: Calculate the clumping index based on the base value of the clumping index and the energy consumption correction factor.

[0019] Further, step S3 includes:

[0020] Step S31: Determine the basic values ​​of grinding time and grinding speed based on the moisture content;

[0021] Step S32: Correct the base value of the grinding time according to the agglomeration index to obtain the grinding time;

[0022] Step S33: During the grinding process, continuously monitor the drive power of the grinding equipment;

[0023] Step S34: If the driving power is greater than or equal to the driving power threshold within a preset time, it is determined that the agglomeration index is higher than expected. The grinding speed base value is corrected according to the agglomeration index and the moisture content to obtain the grinding speed.

[0024] Step S35: Correct the energy consumption correction factor based on the actual unit mass energy consumption of the grinding equipment and the product particle size qualification rate, and apply it to the production of subsequent batches.

[0025] Step S36: Determine the amount of water to be added during mixing based on the actual particle size value of the mixture.

[0026] Further, step S35 includes:

[0027] Step S351: Obtain the historical unit mass energy consumption of the grinding process in the most recent historical batch;

[0028] Step S352: Obtain the product particle size qualification rate of the mixture in the corresponding historical batch;

[0029] Step S353: Detect the actual unit mass energy consumption of the current batch;

[0030] Step S354: Calculate the energy consumption correction factor adjustment amount based on the historical unit mass energy consumption, the actual unit mass energy consumption, and the product particle size qualification rate; update the current energy consumption correction factor based on the energy consumption correction factor adjustment amount.

[0031] Further, step S36 includes:

[0032] Step S361: Detect the median particle size of the mixture as the actual particle size value;

[0033] Step S362: Determine the theoretical water requirement based on the actual particle size value;

[0034] Step S363: Determine the amount of water to be added during mixing and stirring based on the theoretical water requirement and the moisture content.

[0035] Furthermore, in step S31, the basic value of the grinding speed is negatively correlated with the moisture content; the basic value of the grinding time is positively correlated with the moisture content.

[0036] Furthermore, in step S34, the agglomeration index is positively correlated with the correction amount of the base value of the grinding time.

[0037] Furthermore, the powder is a mixture of cement and fly ash, or a mixture of lime and fly ash.

[0038] Furthermore, the first aggregate is coarse aggregate with a particle size of 25mm to 37.5mm.

[0039] Furthermore, the first preset range of the moisture content is 30% to 35%.

[0040] Compared with the prior art, the beneficial effects of the present invention are that, by establishing a dynamic response mechanism between the physical properties of fly ash raw materials and process parameters, the present invention realizes online monitoring and adaptive adjustment of key parameters such as agglomeration degree and moisture content, effectively overcomes the negative impact of fluctuations in the physical properties of fly ash raw materials on product quality stability and energy consumption in the production process, significantly improves the control accuracy and operational economy of the resource utilization process, and provides a reliable technical guarantee for the large-scale resource utilization of municipal solid waste incineration fly ash.

[0041] Furthermore, by monitoring the current signal of the conveyor motor in real time and calculating the agglomeration index, this invention achieves online quantitative assessment of the degree of fly ash agglomeration, providing a reliable basis for the precise adjustment of subsequent grinding process parameters and effectively avoiding process fluctuations and uneven product quality caused by agglomeration.

[0042] Furthermore, by establishing a dynamic matching relationship between moisture content, agglomeration index, and grinding parameters, this invention achieves adaptive optimization of grinding intensity based on material characteristics. This effectively reduces the unit energy consumption of the grinding process while ensuring product particle size, thereby improving the economic efficiency of the entire resource utilization process.

[0043] Furthermore, by introducing a feedback update mechanism for energy consumption correction factors, this invention enables the system to self-correct based on actual energy consumption and product quality performance, gradually optimizing the process control strategy and significantly improving the system's adaptability to long-term process changes and control stability.

[0044] Furthermore, by determining the amount of water added during mixing based on the product particle size, this invention establishes a quality transfer chain between the preceding and subsequent processes, ensuring the sufficiency and uniformity of the hydration reaction in the final product, and effectively improving the mechanical properties and durability of inorganic binder products for road use.

[0045] Furthermore, by organically combining fly ash detoxification treatment with resource utilization processes, this invention achieves efficient value-added utilization of waste while meeting environmental protection requirements, forming a complete technological closed loop and providing a systematic solution for the resource utilization of fly ash from municipal solid waste incineration. Attached Figure Description

[0046] Figure 1 This is a flowchart of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention;

[0047] Figure 2 This is a flowchart of step S2 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention;

[0048] Figure 3 This is a flowchart of step S3 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention;

[0049] Figure 4 This is a flowchart of step S35 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention. Detailed Implementation

[0050] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0051] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0052] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0053] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Please see Figure 1 The diagram shows a flowchart of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention. The present invention provides a method for resource utilization of fly ash from municipal solid waste incineration, comprising:

[0055] Step S1: Detoxify and wash the raw fly ash to obtain fly ash raw material with a moisture content controlled within a first preset range;

[0056] Specifically, the first preset range of the moisture content is 30% to 35%.

[0057] In one specific embodiment, the raw fly ash from municipal solid waste incineration first undergoes a low-temperature pyrolysis detoxification system, treated at 300℃~500℃ for 1~2 hours to decompose organic pollutants such as dioxins; subsequently, the detoxified fly ash is sent to a fly ash water washing and purification system, where it is washed using countercurrent rinsing with clean water at a water-ash mass ratio of 2:1~5:1 to remove soluble salts and some heavy metals; the washed fly ash is then dewatered using a centrifugal dewatering machine or a filter press, with the dewatering time and pressure controlled to stabilize the moisture content of the fly ash raw material between 30% and 35%; preferably, the dewatering time is 10~20 minutes; preferably, the dewatering pressure is 0.5~1.0MPa.

[0058] The dehydrated wet ash meets the requirements of HJ1134—2020 "Technical Specification for Pollution Control of Fly Ash from Municipal Solid Waste Incineration (Trial)" and can be used as a general solid waste resource for recycling. It is stored in the detoxification and washing ash silo for later use. At the same time, the removed washing liquid undergoes a purification treatment system (such as neutralization and precipitation) and an evaporation and crystallization system to recover salts (including sodium chloride and potassium chloride). The condensate is returned to the washing and purification system for recycling. The parameters of the dehydration equipment are adjusted according to the initial moisture content and particle size of the fly ash to ensure uniformity of moisture content.

[0059] Understandably, this step, through low-temperature pyrolysis and water washing detoxification, effectively reduces the toxicity and soluble salt content of fly ash, making it meet the general standards for solid waste resource utilization. The moisture content after dehydration is controlled at 30%–35%, which avoids both excessively low moisture content, which would cause fly ash dust to fly around, affecting the working environment and mixing uniformity, and excessively high moisture content, which would cause fly ash to become sticky, easily agglomerate, and increase the energy consumption of subsequent transportation and grinding. This provides a fly ash raw material with stable physical properties for subsequent steps and a stable parameter basis for subsequent process control. This moisture content range is determined based on the water-holding characteristics of fly ash particles and industrial practice, which can balance fluidity and treatability, ensuring the continuity and economy of the resource utilization process.

[0060] Step S2: The fly ash raw material is fed into a mixing device through a metering and conveying device and mixed with the first aggregate and powder to obtain a premixed material;

[0061] Among them, the current signal of the drive motor of the metering and conveying device is detected in real time during the process of conveying the fly ash raw material. Based on the current signal and the energy consumption correction factor, the agglomeration index characterizing the degree of fly ash agglomeration is calculated. The current signal includes the number of instantaneous peak currents and the standard deviation of current.

[0062] Specifically, the powder is a mixture of cement and fly ash, or a mixture of lime and fly ash.

[0063] Specifically, the first aggregate is coarse aggregate with a particle size of 25mm to 37.5mm.

[0064] In one specific embodiment, fly ash raw material with a detoxified and washed moisture content controlled at 30%–35% is fed into a mixing device via a metering conveyor to be mixed with a first aggregate and powder. The first aggregate is coarse aggregate with a particle size range of 25mm–37.5mm. Preferably, the first aggregate is crushed limestone, or crushed granite, or crushed construction waste. The powder is a mixture of cement and fly ash, preferably with a mass ratio of 1:1, or a mixture of lime and fly ash, preferably with a mass ratio of 1:2. The mixing ratio is set according to product requirements and will not be elaborated here. During the conveying process, the current signal of the drive motor of the metering conveyor is monitored in real time. Based on the current signal and energy consumption correction factor, an agglomeration index is calculated to characterize the degree of fly ash agglomeration. Preferably, the metering conveyor is a screw conveyor, and the mixed materials are conveyed by a mixing belt.

[0065] Please continue reading Figure 2 As shown, it is a flowchart of step S2 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention;

[0066] Specifically, step S2 includes:

[0067] Step S21: Record the number of times the instantaneous peak value of the current signal of the drive motor of the conveying device is greater than the first current threshold during the process of conveying a unit mass of the fly ash raw material, and obtain the number of instantaneous peak values ​​of the current.

[0068] In one specific embodiment, the metering and conveying device employs a screw conveyor, whose drive motor is equipped with a Hall effect current sensor to monitor the current value in real time at a sampling frequency of 1000Hz. During the conveying of a unit mass of fly ash raw material, a first current threshold is set as It1, with units of amperes (A). The instantaneous peak current is defined as follows: within any continuous time window Δt, if the current sample value rises from less than It1 to greater than It1, and remains greater than or equal to td for a duration exceeding It1, it is recorded as a valid instantaneous peak current. The number of peak currents during the conveying of a unit mass of fly ash raw material is counted to obtain the number of instantaneous peak currents Np. Preferably, It1 is taken as 1.2 times the rated current of the drive motor; that is, for a motor with a rated current of 10A, It1 is taken as 12A. Preferably, Δt is taken as 100 milliseconds, and td is taken as 10 milliseconds; Np is a dimensionless positive integer.

[0069] Understandably, the number of instantaneous peak currents directly reflects the frequency of sudden increases in resistance caused by agglomeration of fly ash raw materials during transportation. When fly ash agglomerates, the conveying device encounters jamming or blockage, the load on the drive motor increases instantaneously, and the current peaks. By setting a reasonable current threshold, normal fluctuations can be filtered out, agglomeration events can be accurately captured, providing an intuitive indicator for agglomeration assessment and ensuring the basic reliability of subsequent calculations.

[0070] Step S22: Calculate the standard deviation of the current based on the current value of the drive motor of the conveying device during the conveying of a unit mass of the fly ash raw material;

[0071] In one specific embodiment, during the conveying of a unit mass of fly ash raw material, a current sensor collects current values ​​at a fixed sampling frequency (e.g., 100Hz) to obtain a current data sequence Ii (i=1,2,...,n), where n is the number of sampling points (preferably, 5000 points are collected for conveying 1 ton of fly ash raw material). The average current value Ia is calculated, and then the standard deviation of the current is calculated. The formula for calculating the standard deviation of the current is as follows: ;

[0072] Where σI is the standard deviation of the current, in amperes (A); Ia is the average current, in amperes (A); Ii is a single current sample value, in amperes (A); and n is the number of sampling points. Preferably, the sampling frequency is 100Hz to ensure sufficient detail of fluctuations is captured.

[0073] Understandably, the standard deviation of current quantifies the dispersion of current values ​​during transportation, indirectly characterizing the flow uniformity of fly ash raw materials. If fly ash caking or uneven moisture content leads to large fluctuations in the transportation load and drastic changes in current values, the standard deviation of current increases; conversely, during uniform flow, the standard deviation of current is smaller. This indicator supplements the insufficiency of peak frequency, provides a continuous assessment of the degree of caking, and enhances the comprehensiveness of the overall judgment.

[0074] Step S23: Determine the basic value of the agglomeration index based on the number of instantaneous peak currents and the standard deviation of the current;

[0075] In one specific embodiment, the basic value of the clumping index is calculated based on the number of instantaneous peak currents and the standard deviation of the current. The specific formula for calculating the basic value of the clumping index is as follows: ;

[0076] Wherein, Kb is the basic value of the clumping index, which is dimensionless;

[0077] 'a' is the peak weighting coefficient, which is dimensionless and ranges from 0.6 to 0.8. Preferably, 'a' is 0.7.

[0078] b is the standard deviation weighting coefficient, which is dimensionless and ranges from 0.2 to 0.4. Preferably, a is 0.3.

[0079] Nr is a reference value for the number of peaks, in times. Preferably, Nr is 10 times, which is calibrated based on the typical number of peaks in the transport of a unit mass of fly ash in historical data. This will not be elaborated further.

[0080] σr is the standard deviation reference value, in amperes (A). Preferably, σr is 1.5A, which is calibrated based on the typical value of the current standard deviation in historical data, which will not be elaborated further here.

[0081] Understandably, the base value of the clumping index comprehensively reflects the degree of fly ash clumping by weighted combination of peak frequency and standard deviation. The weighting coefficients are selected based on the relative importance of the two factors influencing clumping: peak frequency directly corresponds to sudden clumping events, thus receiving a higher weight; standard deviation reflects overall fluctuations, receiving a lower weight. Reference values ​​are used to normalize parameters, eliminating the influence of unit values ​​and ensuring that the base value of the clumping index serves as a unified indicator, providing a basis for subsequent adjustments.

[0082] Step S24: Calculate the clumping index based on the base value of the clumping index and the energy consumption correction factor.

[0083] In one specific embodiment, the agglomeration index is the product of the base value of the agglomeration index and the energy consumption correction factor. The energy consumption correction factor is denoted as Ce, which is dimensionless, and its initial value is set to 1.0. It is updated in subsequent steps according to the actual grinding energy consumption. The agglomeration index is denoted as K, which is dimensionless.

[0084] Understandably, the agglomeration index, by introducing an energy consumption correction factor, calibrates the baseline value to account for potential deviations due to changes in equipment condition. This energy consumption correction factor considers long-term factors such as motor efficiency and conveyor wear, making the agglomeration index more adaptable to actual production conditions. This ensures the accuracy and adaptability of agglomeration assessment, providing reliable input for subsequent grinding intensity adjustments and optimizing energy efficiency and product consistency throughout the process.

[0085] Please continue reading Figure 3 The flowchart shown is a step S3 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention.

[0086] Step S3: The premixed material is fed into the grinding equipment through a metering and conveying device, and the first aggregate is used as the grinding medium to crush and grind the premixed material to obtain a mixed material.

[0087] Specifically, based on the agglomeration index and the moisture content, the grinding intensity parameters of the grinding equipment are adjusted, including grinding time and grinding speed; the energy consumption correction factor is corrected according to the actual unit mass energy consumption and product particle size qualification rate of the grinding equipment, and applied to the production of subsequent batches;

[0088] Specifically, step S3 includes:

[0089] Step S31: Determine the basic values ​​of grinding time and grinding speed based on the moisture content;

[0090] Specifically, in step S31, the basic value of the grinding speed is negatively correlated with the moisture content; the basic value of the grinding time is positively correlated with the moisture content.

[0091] In one specific embodiment, the basic grinding time Tb and the basic grinding speed Nb are determined based on the moisture content W (expressed as a percentage) of the fly ash raw material. The specific calculation formula is as follows:

[0092] ;

[0093] Where Tb is the basic grinding time in minutes (min); Nb is the basic grinding speed in revolutions per minute (rpm); W is the moisture content of the fly ash raw material in %; Wmax is the upper limit of moisture content, taken as 35%; and Wr is the reference value of moisture content, taken as 32.5%.

[0094] k1 is the time linearity coefficient, which is calibrated based on regression analysis of process test data. The unit is minutes / %, and the value range is 0.5 to 1.5. Preferably, k1 is 1.0.

[0095] b1 is a time reference constant, which is calibrated according to the basic grinding time requirements. The unit is minutes, and the value range is 5 to 15. Preferably, b1 is 10.

[0096] c1 is a time-secondary correction coefficient, which is calibrated based on the nonlinear effect of moisture content deviation on grinding time. The unit is minutes / %², and the value range is -0.1 to 0.1. Preferably, c1 is 0.05.

[0097] k2 is the speed linearity coefficient, which is calibrated based on regression analysis of process test data. The unit is (revolutions / minute) / %, and the value range is 2 to 6. Preferably, k2 is 4.

[0098] b2 is the rotational speed reference constant, which is calibrated according to the basic grinding speed requirements. The unit is revolutions per minute, and the value range is 20 to 40. Preferably, b2 is 30.

[0099] c2 is the second-order correction coefficient for rotational speed. It is calibrated based on the nonlinear effect of moisture content deviation on grinding speed. The unit is (revolutions / minute) / %2, and the value range is -0.2 to 0.2. Preferably, c2 is 0.1.

[0100] Understandably, the linear coefficient dominates the main trend of change, while the quadratic correction coefficient is used to adjust for nonlinear effects when the moisture content deviates from the reference value, such as process deviations at extremely high or low moisture contents. It is determined based on least squares regression analysis of a large amount of historical process data to ensure that the model prediction is consistent with the actual process response.

[0101] Understandably, moisture content directly affects the adhesion and flowability of materials. Higher moisture content usually leads to increased material viscosity, requiring longer grinding times and reduced rotation speeds to prevent equipment overload and material adhesion. Lower moisture content results in better material flowability but also increases the likelihood of dust generation, necessitating shorter grinding times and increased rotation speeds. The introduction of quadratic terms enhances the model's adaptability to extreme moisture content conditions, more accurately reflecting the nonlinear behavior in actual processes. This provides a reliable benchmark for subsequent dynamic corrections, ensuring the grinding process remains stable and efficient under different moisture content conditions.

[0102] Step S32: Correct the base value of the grinding time according to the agglomeration index to obtain the grinding time;

[0103] In one specific embodiment, the base grinding time Tb is corrected based on the agglomeration index K to obtain the final grinding time. The specific correction formula is as follows: ;

[0104] Where Tf is the corrected grinding time, in minutes (min).

[0105] 'a' is a linear correction coefficient, which is calibrated according to the degree of linear influence of the agglomeration index on the grinding time. It is dimensionless and ranges from 0.05 to 0.15. Preferably, 'a' is 0.1.

[0106] b is a secondary correction coefficient, which is calibrated based on the nonlinear effect of the agglomeration index on the grinding time. It is dimensionless and ranges from -0.05 to 0.05. Preferably, b is 0.02.

[0107] Understandably, the correction coefficients a and b were determined based on multiple regression analysis of the relationship between agglomeration degree and grinding time in historical production data. The linear coefficient a reflects the direct proportional impact of increased agglomeration index on grinding time, while the quadratic coefficient b is used to capture potential acceleration or deceleration nonlinear effects under high agglomeration index, such as abrupt changes in grinding efficiency when agglomeration is severe. The range of coefficient values ​​was determined through sensitivity analysis to ensure the robustness and economy of the correction.

[0108] Understandably, a high agglomeration index indicates severe agglomeration of the fly ash raw material, necessitating increased grinding time to ensure thorough crushing and prevent uneven product particle size. The quadratic term allows the model to handle nonlinear behavior when agglomeration is extremely high, such as fluctuations in grinding efficiency caused by changes in the hardness of the agglomerates, thus preventing energy waste from over-correction or quality problems from under-correction. This feedback mechanism based on real-time indicators enhances the process's adaptability, maintaining stable product quality and optimized energy efficiency when dealing with fluctuations in the physical properties of fly ash.

[0109] Step S33: During the grinding process, the driving power of the grinding equipment is continuously monitored.

[0110] In one specific embodiment, during the grinding process, a power sensor installed on the drive motor of the grinding equipment continuously monitors the drive power. The power sensor employs a three-phase power measurement principle, acquiring power data in real time at a sampling frequency of 100Hz, with a measurement accuracy of ±0.5%. The detected power data is transmitted to the control system via industrial Ethernet for real-time processing and storage. Preferably, the power sensor's range covers 50% to 150% of the grinding equipment's rated power, ensuring accurate measurement under both normal and abnormal operating conditions.

[0111] Understandably, drive power directly reflects the workload of the grinding equipment and is a crucial indicator for judging the equipment's operating status and changes in material characteristics. Continuous monitoring can promptly detect abnormal operating conditions, providing data support for subsequent speed adjustments and ensuring the safe and stable operation of the equipment.

[0112] Step S34: If the driving power is greater than or equal to the driving power threshold within a preset time, it is determined that the agglomeration index is higher than expected. The grinding speed base value is corrected according to the agglomeration index and the moisture content to obtain the grinding speed.

[0113] Specifically, in step S34, the agglomeration index is positively correlated with the correction amount of the base value of the grinding time.

[0114] In one specific embodiment, when the driving power is detected to be continuously greater than or equal to the driving power threshold for a preset time, it is determined that the degree of material agglomeration is higher than expected, and the grinding speed is dynamically corrected. The corrected grinding speed is calculated using the following formula: ;

[0115] Where Nf is the corrected grinding speed, in revolutions per minute;

[0116] Kr is the agglomeration index reference value, which is set to 1.0. It is based on the ideal agglomeration degree under the process optimization target.

[0117] P represents the real-time drive power, measured in kilowatts.

[0118] Pt is the driving power threshold, which is 75% of the rated power of the grinding equipment, and the unit is kilowatt;

[0119] η is the rotation speed adjustment coefficient, which is calibrated according to the matching relationship between material characteristics and grinding efficiency. It is dimensionless and its value ranges from -0.2 to -0.05. Preferably, η is -0.12.

[0120] m is the agglomeration influence factor, which characterizes the influence intensity of the agglomeration degree on grinding kinetics. It is dimensionless and ranges from 0.6 to 1.0. Preferably, m is 0.8.

[0121] n is the power response factor, which characterizes the sensitivity of power changes to grinding intensity adjustment. It is dimensionless and ranges from 0.4 to 0.8. Preferably, n is 0.6.

[0122] The preset time ts is determined based on the process response characteristics, and the unit is seconds (s). The value range is 15 to 30 seconds, and preferably, ts is 20 seconds.

[0123] Understandably, a negative speed adjustment coefficient indicates that the speed needs to be appropriately reduced when agglomeration is severe. The agglomeration influence factor reflects the changing characteristics of material crushing under different degrees of agglomeration. The power response factor reflects the degree of influence of the deviation between actual power and the threshold on the adjustment range. The reference values ​​are set based on optimization and determination of a large amount of process test data to ensure the accuracy of the correction and the applicability of the process. Those skilled in the art can make adaptive adjustments to the values ​​and selection of parameters according to the actual situation, which will not be elaborated further here.

[0124] Understandably, this step achieves a precise match between grinding intensity and material characteristics by establishing a dynamic speed correction mechanism based on power feedback. When the drive power remains consistently high, it indicates that the degree of material agglomeration exceeds expectations. Maintaining the original speed at this point would lead to decreased grinding efficiency and uneven product quality. By appropriately reducing the speed, the interaction between the grinding media and the material can be optimized, reducing ineffective collisions and energy loss caused by severe agglomeration, allowing grinding energy to be used more effectively in the material crushing process. This adjustment strategy based on real-time power monitoring can automatically adapt to changes in material characteristics, providing a more suitable grinding intensity when the degree of agglomeration is high, thereby ensuring the uniformity and stability of the final product particle size and improving the quality control level of the entire resource recovery process.

[0125] Please continue reading Figure 4 The flowchart shown is a step S35 of the method for resource utilization of fly ash from municipal solid waste incineration according to the present invention.

[0126] Step S35: Correct the energy consumption correction factor based on the actual unit mass energy consumption of the grinding equipment and the product particle size qualification rate, and apply it to the production of subsequent batches.

[0127] Specifically, step S35 includes:

[0128] Step S351: Obtain the historical unit mass energy consumption of the grinding process in the most recent historical batch;

[0129] In one specific embodiment, historical energy consumption data per unit mass of grinding from the N most recent historical batches is obtained from the production process database. Historical energy consumption per unit mass is obtained by dividing the total energy consumption of each historical batch by the total mass of material processed, and is expressed in kilowatt-hours per ton. The number of historical batches is determined based on process stability and data representativeness requirements, ranging from 5 to 20 batches. Preferably, data from the 10 most recent batches are selected as a reference baseline.

[0130] Understandably, the core purpose of obtaining historical unit mass energy consumption is to establish a benchmark for process energy consumption. In continuous production, historical energy consumption data represents the level of process energy efficiency achieved under specific material characteristics and equipment conditions, reflecting the energy consumption characteristics of the system during normal operation. By comparing the actual energy consumption of the current batch with this historical benchmark, energy consumption anomalies caused by significant fluctuations in the physical properties of fly ash raw materials (such as agglomeration degree and moisture content) can be effectively identified. This comparison mechanism provides an objective basis for subsequent evaluation of process status and determination of whether control strategies need to be adjusted.

[0131] Step S352: Obtain the product particle size qualification rate of the mixture in the corresponding historical batch;

[0132] In one specific embodiment, the particle size pass rate of the corresponding historical batches of the mixed material products is obtained from the quality inspection database. The product particle size pass rate is defined as follows: representative samples are taken from each historical batch of the finished mixed material according to the requirements of GB / T 6679 "General Rules for Sampling of Solid Chemical Products"; the obtained samples are analyzed using a laser particle size analyzer according to GB / T 19077 "Laser Diffraction Method for Particle Size Distribution" standard to obtain their historical particle size values. The proportion of all qualified historical particle size values ​​of the corresponding historical batch to the total number of historical particle size values ​​is the product particle size pass rate, denoted as Qh, in %. The standard for qualified particle size is defined as: the median particle size D50 of the sample is within the preset target particle size range [Dmin, Dmax]. The target particle size range is determined according to the technical specifications of the final road inorganic binder product, with a lower limit Dmin of 45 micrometers and an upper limit Dmax of 75 micrometers.

[0133] Understandably, linking the adjustment of the energy consumption correction factor to this pass rate means that the system's optimization direction is directly anchored to the final product quality. When the pass rate of product granularity in historical batches is high, it indicates that the process parameters at that time (related to the energy consumption at that time) were effective; conversely, if the pass rate is low, it suggests that the process effect corresponding to that energy consumption level is not good. This correlation mechanism ensures that the system pursues energy reduction without sacrificing product quality, achieving a closed-loop unity of energy efficiency improvement and quality assurance.

[0134] Step S353: Detect the actual unit mass energy consumption of the current batch;

[0135] In one specific embodiment, the actual energy consumption per unit mass is calculated by measuring the total energy consumption of the current batch of grinding by a smart meter installed in the power supply circuit of the grinding equipment, and dividing it by the total mass of the material processed in that batch. It is denoted as Ec, and the unit is kilowatt-hours per ton.

[0136] Step S354: Calculate the adjustment amount of the energy consumption correction factor based on the historical unit mass energy consumption, the actual unit mass energy consumption, and the product particle size qualification rate; update the current energy consumption correction factor based on the adjustment amount of the energy consumption correction factor.

[0137] In a specific embodiment, the formula for calculating the energy consumption correction factor adjustment is as follows: ;

[0138] in,

[0139] ΔCe is the adjustment amount of the energy consumption correction factor, which is dimensionless;

[0140] Ec represents the actual unit mass energy consumption of the current batch, in kilowatt-hours per ton.

[0141] Eh is the historical average energy consumption per unit mass, expressed in kilowatt-hours per ton.

[0142] Qh represents the particle size qualification rate of the corresponding historical batch, in percentage (%).

[0143] ω is an adjustment intensity coefficient, which is calibrated according to the system response speed and stability requirements. It is dimensionless and its value ranges from 0.1 to 0.3. Preferably, ω is 0.2.

[0144] f is the quality weight index, which characterizes the degree of influence of the quality pass rate on the correction intensity. It is dimensionless and ranges from 0.5 to 1.5. Preferably, f is 1.0.

[0145] The updated formula for calculating the energy consumption correction factor is as follows: ;

[0146] This is the updated energy consumption correction factor, which is dimensionless.

[0147] This is the current energy consumption correction factor, which is dimensionless.

[0148] Understandably, this correction formula achieves intelligent updating of the energy consumption correction factor through multi-parameter coordination. The adjustment intensity coefficient ω controls the correction magnitude, avoiding system oscillations caused by over-adjustment; the quality weight index f reflects the importance of product quality in the correction decision, with a lower quality pass rate resulting in a stronger correction intensity. The formula employs relative deviation calculation and exponential weighting to ensure the stability and adaptability of the correction.

[0149] Understandably, when actual energy consumption deviates significantly from historical levels, the system automatically identifies process anomalies or changes in material properties, and adjusts subsequent agglomeration index calculations through correction factors. Simultaneously, the product quality pass rate is introduced as an adjustment factor for the correction weight, ensuring stronger correction when quality fails to meet standards and moderate adjustments when quality is stable. This self-learning and self-optimization mechanism enables the system to gradually adapt to long-term process changes and equipment status evolution, continuously improving the stability and economy of the entire resource recovery process, demonstrating the advanced nature and practicality of the intelligent control system.

[0150] Step S36: Determine the amount of water to be added during mixing based on the particle size value of the mixture.

[0151] Specifically, step S36 includes:

[0152] Step S361: Detect the median particle size of the mixture as the particle size value;

[0153] In one specific embodiment, the actual particle size of the mixture is obtained by taking online samples from the discharge port after grinding, and taking representative samples in accordance with the requirements of GB / T 6679 "General Rules for Sampling of Solid Chemical Products"; the obtained samples are then analyzed using a laser particle size analyzer in accordance with the GB / T 19077 "Laser Diffraction Method for Particle Size Distribution" standard to obtain the actual particle size value, denoted as D0, in micrometers.

[0154] Step S362: Determine the theoretical water requirement based on the particle size value;

[0155] In one specific embodiment, the theoretical water requirement W_t (unit: kg / unit mass fly ash) is determined based on the detected particle size value D0 (unit: micrometers) of the mixture. The specific calculation formula is as follows: ;

[0156] Wherein, α is the specific surface area influence coefficient, which is determined based on the surface hydration water requirement of fly ash and powder particles, with the unit being kg·micron / unit mass fly ash, and the value range is 150 to 250, preferably α is 200; β is the basic water requirement of cementitious materials, which is determined based on the standard consistency water requirement of cement, fly ash and other cementitious components in the formula, with the unit being kg / unit mass fly ash, and the value range is 0.25 to 0.35, preferably β is 0.30.

[0157] Understandably, this formula is based on the fundamental relationship between particle specific surface area and water demand. The specific surface area influence coefficient α quantifies the increase in water demand caused by a unit increase in specific surface area, and its value is obtained through regression analysis of standard consistency experimental data of fly ash samples with different particle sizes. The basic water demand β of the cementitious material represents the basic amount of water required for the hydration reaction of the cementitious material itself when the influence of fly ash particle size is ignored. This formula has a simple structure and clear physical meaning, and can accurately reflect the objective law that as the particle size of the mixture decreases (D0 value decreases) and the specific surface area increases, the theoretical water demand increases accordingly.

[0158] It is understandable that the particle size of the mixture directly determines its total specific surface area, and the hydration reaction occurs on the particle surface. Therefore, the water requirement is inversely proportional to the specific surface area, i.e., to the particle size. By introducing the above formula, the system can accurately calculate the theoretical amount of water required for the full hydration of the cementitious material based on the real-time detected grinding effect (particle size value). This provides a core basis for subsequent precise water addition control, avoiding insufficient or excessive water addition due to experience-based operation, thereby ensuring the strength and stability of the final product.

[0159] Step S363: Determine the amount of water to be added during mixing and stirring based on the theoretical water requirement and the moisture content.

[0160] In a specific embodiment, the formula for calculating the amount of water added is as follows: ;

[0161] Wadd represents the additional water required for mixing, i.e., the actual amount of water added, expressed in kilograms per unit mass of fly ash; Wt represents the theoretical water requirement calculated in step S362, expressed in kilograms per unit mass of fly ash; W represents the moisture content of the fly ash raw material in step S1, expressed as a percentage (%). In the formula, (W / 100) represents the conversion of the percentage moisture content to a mass fraction, i.e., the mass of water already contained in a unit mass of fly ash raw material.

[0162] `max` is a function that takes the maximum value, ensuring that the calculated result is not less than 0. When the moisture content of the fly ash raw material itself exceeds the theoretical water requirement, the calculated result is 0, meaning no additional water needs to be added.

[0163] Understandably, the (W / 100) term in the formula converts the percentage moisture content into a decimal representation of the water content per unit mass of fly ash. The max function ensures that the calculation result is not negative; that is, when the moisture content of the fly ash raw material itself exceeds the theoretical water requirement, no additional water is added.

[0164] It is understandable that the moisture retained in the fly ash raw material after detoxification and washing is already part of the material system and can be effectively utilized in subsequent mixing and hydration processes. Therefore, the actual amount of additional water needed should be the net value after deducting this existing moisture from the theoretical total water requirement. This calculation method avoids the ineffective addition and waste of water. More importantly, by precisely controlling the total water-cement ratio, it prevents a series of product quality problems caused by excessively high water-cement ratios, such as slurry segregation, decreased strength, or excessive drying shrinkage.

[0165] Step S4: Mix the mixture, the second aggregate, the third aggregate, and water in a mixing device to obtain an inorganic binder product for road use.

[0166] In practice, a twin-shaft mixer was used as the mixing equipment.

[0167] The amount of water added during mixing is determined based on the particle size value of the mixture.

[0168] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of fly ash from municipal solid waste incineration, characterized in that, include: Step S1: Detoxify and wash the raw fly ash to obtain fly ash raw material with a moisture content controlled within a first preset range; Step S2: The fly ash raw material is fed into a mixing device through a metering and conveying device and mixed with the first aggregate and powder to obtain a premixed material; Among them, the current signal of the drive motor of the metering and conveying device is detected in real time during the process of conveying the fly ash raw material. Based on the current signal and the energy consumption correction factor, the agglomeration index characterizing the degree of fly ash agglomeration is calculated. The current signal includes the number of instantaneous peak currents and the standard deviation of current. Step S2 includes: Step S21: Record the number of times the instantaneous peak value of the current signal of the drive motor of the metering and conveying device is greater than the first current threshold during the process of conveying a unit mass of the fly ash raw material, and obtain the number of instantaneous peak values ​​of the current. Step S22: Calculate the standard deviation of the current based on the current value of the drive motor of the metering and conveying device during the conveying of a unit mass of the fly ash raw material; Step S23: Determine the basic value of the agglomeration index based on the number of instantaneous peak currents and the standard deviation of the current; Step S24: Calculate the clumping index based on the base value of the clumping index and the energy consumption correction factor; Step S3: The premixed material is fed into the grinding equipment through a metering and conveying device, and the first aggregate is used as the grinding medium to crush and grind the premixed material to obtain a mixed material. Specifically, based on the agglomeration index and the moisture content, the grinding intensity parameters of the grinding equipment are adjusted, including grinding time and grinding speed; the energy consumption correction factor is corrected according to the actual unit mass energy consumption of the grinding equipment and the product particle size qualification rate, and applied to the production of subsequent batches; Step S3 includes: Step S31: Determine the basic values ​​of grinding time and grinding speed based on the moisture content; Step S32: Correct the base value of the grinding time according to the agglomeration index to obtain the grinding time; Step S33: During the grinding process, continuously monitor the drive power of the grinding equipment; Step S34: If the driving power is greater than or equal to the driving power threshold within a preset time, it is determined that the agglomeration index is higher than expected. The grinding speed base value is corrected according to the agglomeration index and the moisture content to obtain the grinding speed. Step S35: Correct the energy consumption correction factor based on the actual unit mass energy consumption of the grinding equipment and the product particle size qualification rate, and apply it to the production of subsequent batches. Step S36: Determine the amount of water to be added during mixing based on the actual particle size value of the mixture. Step S4: Mix the mixture, the second aggregate, the third aggregate, and water in a mixing device to obtain an inorganic binder product for road use. The amount of water added during mixing is determined based on the actual particle size of the mixture.

2. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, Step S35 includes: Step S351: Obtain the historical unit mass energy consumption of the grinding process in the most recent historical batch; Step S352: Obtain the product particle size qualification rate of the mixture in the corresponding historical batch; Step S353: Detect the actual unit mass energy consumption of the current batch; Step S354: Calculate the energy consumption correction factor adjustment amount based on the historical unit mass energy consumption, the actual unit mass energy consumption, and the product particle size qualification rate; update the current energy consumption correction factor based on the energy consumption correction factor adjustment amount.

3. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 2, characterized in that, Step S36 includes: Step S361: Detect the median particle size of the mixture as the actual particle size value; Step S362: Determine the theoretical water requirement based on the actual particle size value; Step S363: Determine the amount of water to be added during mixing and stirring based on the theoretical water requirement and the moisture content.

4. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, In step S31, the basic value of the grinding speed is negatively correlated with the moisture content; the basic value of the grinding time is positively correlated with the moisture content.

5. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, In step S34, the agglomeration index is positively correlated with the correction amount of the basic grinding time value.

6. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, The powder is a mixture of cement and fly ash, or a mixture of lime and fly ash.

7. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, The first aggregate is coarse aggregate with a particle size of 25mm to 37.5mm.

8. The method for resource utilization of fly ash from municipal solid waste incineration according to claim 1, characterized in that, The first preset range of the moisture content is 30% to 35%.

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