Full-automatic coal sample preparation analysis method and system

Abstract

The invention relates to the technical field of coal full-automatic sample preparation, in particular to a coal full-automatic sample preparation analysis method and system.The method comprises the steps that water regulation and control are conducted on a coal sample through stepped variable frequency microwaves, dielectric properties are used for real-time monitoring, and microwave parameters are dynamically adjusted to achieve water closed-loop control; when the moisture reaches a target interval, the coal sample is subjected to self-fragmentation along a mineral interface by adopting a surface acoustic wave resonance technology; then exciting coal sample fluorescence through ultraviolet light and detecting the attenuation rate of the coal sample fluorescence so as to judge the oxidation degree; the division proportion is dynamically adjusted based on the oxidation monitoring result to prevent the sample from being degraded. The system comprises a preprocessing unit, a core processing unit, an optical monitoring unit, a division execution unit and a central control system, and each unit is deeply coupled with an execution stream through a data stream. The full-closed-loop self-optimization of the sample preparation process is realized, and the moisture regulation and control uniformity, the crushing energy utilization rate, the oxidation inhibition capability and the sample fidelity are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fully automatic coal sampling, and in particular to a fully automatic coal sampling analysis method and system. Background Art

[0002] The fully automated coal sampling and analysis system is a critical precursor to coal quality testing. Its core task is to transform raw coal samples into representative analytical samples through standardized crushing, drying, and reduction processes. The basic process involves high-temperature drying to remove moisture from the coal sample, followed by mechanical extrusion crushing to the target particle size, and finally manual reduction and packaging. This model relies on operator experience, and the sample transfer process is exposed to the open environment. Traditional systems typically consist of independently operated mechanical crushing units, hot air drying devices, and manual reduction tools, each of which is physically separated and has operational breakpoints.

[0003] In the moisture control link of the existing fully automatic coal sample preparation and analysis system, traditional hot air drying adopts a heat conduction method from the surface to the inside, which can easily cause the surface of the coal sample to overheat and coke, while leaving moisture inside. Not only is the moisture distribution uniform, but it also causes pyrolysis degradation of the coal quality. Mechanical extrusion in the crushing stage generates strong shear forces, which leads to non-selective fracture of the mineral interface, resulting in ineffective micronization and particle size segregation, and seriously weakening the representativeness of the sample. In addition, the mechanical energy of the crushing process is converted into thermal energy, which causes the temperature of the coal sample to rise. Combined with the long-term air exposure during manual reduction, it causes an oxidation chain reaction, and key indicators such as volatile matter undergo irreversible decay. The independent operation mode of each unit equipment isolates information, disconnects moisture control from crushing parameters, and oxidation monitoring results cannot guide the reduction operation in real time, resulting in the lack of a protection mechanism to prevent degradation.

[0004] Traditional methods struggle to achieve dynamic coupled control of moisture, crushing, and oxidation. Localized overdrying of the moisture distribution increases crushing energy consumption, while heat accumulation from mechanical extrusion accelerates oxidation. Human intervention further amplifies error transmission, making sample preparation accuracy and efficiency difficult to meet modern coal quality inspection requirements. Therefore, a closed-loop, collaborative, fully automated sample preparation system and method are urgently needed to address these issues. Summary of the Invention

[0005] To solve the problems existing in the background technology, the present invention provides a fully automatic coal sampling and analysis method, comprising the following steps:

[0006] S1. Multi-frequency pretreatment of coal samples: the original coal sample is sent into the microwave treatment chamber and moisture is controlled by step-by-step variable frequency microwave radiation;

[0007] S2, dynamic moisture closed-loop control: through real-time monitoring of the dielectric properties of coal samples, dynamic calculation of effective moisture value and feedback adjustment of microwave parameters;

[0008] S3, Acoustic Resonance Precision Crushing: When the coal sample reaches the target moisture range, surface acoustic wave vibrations of a specific frequency are applied to cause the coal sample to self-fragment;

[0009] S4. Optical monitoring of oxidation degree: using UV LED array to detect the oxidation state of coal sample surface in real time;

[0010] S5. Intelligent reduction adjustment: Dynamically adjust the reduction ratio based on oxidation monitoring results to prevent sample degradation.

[0011] Furthermore, the specific process of S1 includes:

[0012] 200-500g of raw coal sample is placed into the waveguide cavity and microwave frequency is continuously decreased. The treatment process meets the following requirements:

[0013] ;

[0014] in, express The microwave frequency at the moment; Represents time parameters; Indicates the maximum operating frequency ; Indicates the minimum operating frequency ; Indicates a total processing time of 180-300 seconds.

[0015] Furthermore, the specific process of S2 includes:

[0016] The dielectric parameters are collected every 10 seconds by a vector network analyzer, the effective moisture value is calculated, and the microwave power is adjusted in real time. The calculation model is:

[0017] ;

[0018] in, Indicates the effective moisture value; represents the dielectric-moisture conversion coefficient; represents the dielectric loss factor; represents the microwave angular frequency; Indicates the true density of coal; Indicates the initial value of moisture attenuation; represents the decay rate coefficient; Indicates drying time.

[0019] Furthermore, the specific process of S3 includes:

[0020] when The piezoelectric ceramic array is activated at this time, and a resonant crushing wave is generated according to the mechanical properties of the coal body. The frequency calculation formula is:

[0021] ;

[0022] in, represents the surface acoustic wave frequency; Indicates the speed of sound wave propagation; Indicates the target granularity; represents the elastic modulus; represents the moisture correction factor; Indicates compressive strength.

[0023] Furthermore, the duration of the crushing process is determined by the following formula:

[0024] ;

[0025] in, Indicates the duration of vibration; Indicates that the maximum allowed duration is 120 seconds; Indicates the target granularity; Indicates compressive strength; Indicates the effective moisture value; Represents a natural constant.

[0026] Furthermore, the specific process of S4 includes:

[0027] Using a 365 nm UV LED array, the degree of oxidation is determined by the fluorescence intensity decay rate:

[0028] ;

[0029] in, represents the fluorescence decay rate; represents the initial fluorescence intensity; express Fluorescence intensity at each moment; Indicates the exposure time of coal sample.

[0030] Furthermore, the specific process of S5 includes:

[0031] The reduction ratio is dynamically adjusted according to the oxidation rate. The adjustment formula is:

[0032] ;

[0033] in, Indicates the actual reduction ratio; Indicates the base reduction ratio is 1:12; represents the measured fluorescence decay rate.

[0034] The present invention provides a fully automatic coal sampling and analysis system, comprising:

[0035] The pre-processing unit includes a variable frequency microwave generator, a waveguide processing chamber and a coal sample conveyor belt with a built-in weighing sensor;

[0036] The core processing unit is a resonant crushing tube wrapped by a piezoelectric ceramic vibration ring, with a dielectric measurement probe embedded in the tube wall;

[0037] Optical monitoring unit, a fluorescence detection component consisting of a quartz window, a UV LED array, and a spectrum analyzer;

[0038] The reduction execution unit includes a rotary reducer, a pneumatic diverter valve and a sample bottle turntable;

[0039] Central control system, integrating industrial computers, data acquisition cards and PLC controllers;

[0040] Among them, the discharge port of the waveguide processing cavity is connected to the feed end of the resonance crushing tube, the end of the crushing tube is connected to the feed port of the rotary divider, the output end of the dielectric measurement probe and the spectrum analyzer is connected to the industrial computer through the data acquisition card, and the output end of the PLC controller controls the variable frequency microwave generator, piezoelectric ceramic vibration ring and pneumatic diverter valve respectively.

[0041] In a preferred solution, the piezoelectric ceramic vibration ring is made of lead zirconate titanate material.

[0042] In a preferred embodiment, the surface of the quartz window is coated with a nano-coating that prevents coal dust from adhering.

[0043] The beneficial effects achieved by the present invention are:

[0044] The present invention designs a dielectric-mechanical coupling moisture control mechanism, which achieves targeted moisture removal of coal samples through adaptive switching of microwave frequency bands. Different from the traditional heat conduction drying method, it uses the dielectric loss characteristics to achieve synchronous control of internal and external moisture, ensuring the uniformity of moisture distribution while avoiding coal pyrolysis.

[0045] This invention proposes a surface acoustic wave resonance crushing method, which achieves precise energy transfer by stimulating the coal's natural frequency. This non-contact crushing method changes the traditional mechanical extrusion mode, allowing the coal sample to self-disintegrate along the mineral interface within a specific stress field, thus reducing ineffective energy dissipation and pulverization at the source.

[0046] This invention builds a multi-module, closed-loop collaborative system, integrating moisture control, resonance crushing, oxidation monitoring, and intelligent fractionation into an organic whole. Through deep coupling of data flow and execution flow, each unit achieves self-optimization capabilities throughout the entire sample preparation process. This system ensures sample representativeness while establishing a protection system against degradation, significantly improving moisture control efficiency, crushing energy utilization, oxidation inhibition, and sample fidelity. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1The present invention is a flow chart of the fully automatic coal sample preparation and analysis method.

[0048] Figure 2 It is a system architecture diagram of the fully automatic coal sampling and analysis system of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions of the present invention will be described clearly and completely below in conjunction with the drawings in the present invention. In addition, the forms of the various structures described in the following embodiments are merely examples. The present invention is not limited to the various structures described in the following embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] Reference Figure 1-Figure 2 The present invention designs a fully automatic coal sampling and analysis method, which includes the following steps: S1, multi-band pretreatment of coal samples; sending the original coal sample into the microwave processing chamber, and using step-type variable frequency microwave radiation to regulate the moisture; S2, dynamic moisture closed-loop control; by real-time monitoring of the dielectric properties of the coal sample, dynamically calculating the effective moisture value and feedback-adjusting the microwave parameters; S3, acoustic resonance precise crushing; when the coal sample reaches the target moisture range, applying surface acoustic wave vibration of a specific frequency to make the coal sample self-fragmented; S4, optical monitoring of oxidation degree; using an ultraviolet LED array to detect the surface oxidation state of the coal sample in real time; S5, intelligent reduction adjustment; dynamically adjusting the reduction ratio based on the oxidation monitoring results to prevent sample deterioration.

[0051] The specific process of S1 includes: placing 200-500g of raw coal sample into the waveguide cavity and performing a continuous microwave frequency reduction operation. The processing process meets the following requirements:

[0052] ;

[0053] in, express Microwave frequency at the moment (Hz); represents the time parameter (s); Indicates the maximum operating frequency (Hz); Indicates the minimum operating frequency (Hz); Indicates the total processing time (s) between 180 and 300 seconds.

[0054] The specific process of S2 includes:

[0055] The dielectric parameters are collected every 10 seconds by a vector network analyzer, the effective moisture value is calculated, and the microwave power is adjusted in real time. The calculation model is:

[0056] ;

[0057] in, Indicates the effective moisture value (%); represents the dielectric-moisture conversion coefficient (0.85-1.15); Indicates dielectric loss factor (0.02-0.15); represents the microwave angular frequency (rad / s); Indicates the true density of coal (1.2-1.8 g / cm³); Indicates the initial value of moisture attenuation (2%-4%); represents the decay rate coefficient (0.01-0.05 s⁻¹); Indicates drying time (s).

[0058] The specific process of S3 includes:

[0059] when The piezoelectric ceramic array is activated at this time, and a resonant crushing wave is generated according to the mechanical properties of the coal body. The frequency calculation formula is:

[0060] ;

[0061] in, Indicates the surface acoustic wave frequency (18-35 kHz); Indicates the speed of sound waves (800-1200 m / s); Indicates target particle size (0.2-3.0 mm); represents the elastic modulus (0.5-2.5 GPa); represents the moisture correction factor (0.6-1.1); Indicates compressive strength (10-40 MPa).

[0062] The duration of the crushing process is determined by the following formula:

[0063] ;

[0064] in, Indicates the vibration duration (15-90 s); Indicates that the maximum allowed duration is 120 seconds; Indicates the target particle size (mm); Indicates compressive strength (MPa); Indicates the effective moisture value (decimal form); Represents a natural constant.

[0065] The specific process of S4 includes:

[0066] Using a 365 nm UV LED array, the degree of oxidation is determined by the fluorescence intensity decay rate:

[0067] ;

[0068] in, represents the fluorescence decay rate (0.1-2.0% / s); represents the initial fluorescence intensity (au); express Fluorescence intensity at time (au); Indicates the exposure time of coal sample (60-600 s).

[0069] The specific process of S5 includes:

[0070] The reduction ratio is dynamically adjusted according to the oxidation rate. The adjustment formula is:

[0071] ;

[0072] in, Indicates the actual reduction ratio (1:8 to 1:16); Indicates the base reduction ratio is 1:12; Represents the measured fluorescence decay rate (% / s).

[0073] The present invention designs a fully automatic coal sample preparation and analysis system, which includes: a pre-processing unit, comprising a variable frequency microwave generator, a waveguide processing chamber, and a coal sample conveyor belt with a built-in weighing sensor; a core processing unit, comprising a resonant crushing tube wrapped by a piezoelectric ceramic vibration ring, with a dielectric measurement probe embedded in the tube wall; an optical monitoring unit, comprising a fluorescence detection assembly consisting of a quartz window, an ultraviolet LED array, and a spectrum analyzer; and a reduction execution unit, comprising a rotary reducer, a pneumatic diverter valve, and a sample bottle turntable.

[0074] The central control system integrates an industrial computer, a data acquisition card, and a PLC controller. The waveguide processing chamber outlet is connected to the resonant crushing tube feed port, and the crushing tube terminal is connected to the rotary divider feed port. The dielectric measurement probe and spectrum analyzer outputs are connected to the industrial computer via a data acquisition card. The PLC controller output controls the variable frequency microwave generator, piezoelectric ceramic vibrating ring, and pneumatic diverter valve. The piezoelectric ceramic vibrating ring is made of lead zirconate titanate. The quartz window surface is coated with a nano-coating to prevent coal dust adhesion. The following is a detailed description:

[0075] A fully enclosed feed hopper is located at the system entrance, with a twin-screw feeder mounted at its base. These counter-rotating screws push the raw coal sample onto a conveyor belt at a constant speed of 15 rpm. This design eliminates sample congestion while maintaining a constant feed rate of 100-200 g / min. The conveyor belt utilizes a double-layer PTFE-coated steel mesh structure, with a high-precision load cell embedded in its base. This monitors coal sample mass fluctuations to an accuracy of ±0.1 gram in real time, providing quality benchmark data for subsequent processing.

[0076] Coal samples are conveyed via a conveyor belt into a microwave processing chamber, which utilizes a rectangular waveguide structure and an aluminum nitride ceramic protective layer on its inner wall. A microwave generator connects the left and right radiation ports via an orthogonal mode converter, with an output frequency continuously adjustable between 915 MHz and 2.45 GHz. Key to this is the control circuit's dynamic analysis of the dielectric analyzer signal. Upon detecting an abnormally high dielectric loss factor in the coal sample, the system automatically switches to low-frequency mode. This design significantly improves the drying efficiency of high-volatile coals and prevents pyrolysis.

[0077] After moisture control, the coal sample enters a resonant crushing tube, where piezoelectric ceramic vibrating rings are densely arranged around the outer circumference. The ceramic elements are made of 8mm diameter discs made of lead zirconate titanate. The axial gradient arrangement allows the spacing between the elements to taper from 12mm at the top to 8mm at the bottom. This innovative layout creates a spiral stress field within the tube. Combined with the 3mm-thick titanium alloy acoustic resonance layer on the tube wall, this reduces crushing energy consumption to half that of conventional equipment. Crushing parameters are automatically calculated by a central control system based on the target particle size, ensuring that the vibration frequency precisely matches the mechanical properties of the coal.

[0078] An optical detection area is set up after the crushing section, and the quartz window is placed at an angle of 75 degrees on the side wall of the pipe to prevent coal powder accumulation. The inside of the window is coated with a 20nm thick indium tin oxide conductive film, which generates a weak electric field when powered to repel coal dust. The upper ultraviolet LED array irradiates the coal flow at a 45-degree angle, and the wavelength is locked at 365nm. The bottom fiber optic probe collects 580-620nm fluorescence signals in coaxial reflection mode, reducing the oxidation detection response time to 500 milliseconds. The working principle of the ultraviolet LED array is: a 365 nm wavelength ultraviolet LED array is used to irradiate the coal flow at a 45-degree angle to stimulate the surface of the coal sample to produce fluorescence (main band 580-620 nm). The optical fiber probe built into the quartz window captures the fluorescence signal in coaxial reflection mode, and the fluorescence intensity change is measured in real time by a spectrometer. The core calculation model is the fluorescence decay rate formula:

[0079]

[0080] in is the initial fluorescence intensity, is the real-time fluorescence intensity, is the exposure time of the coal sample. It directly reflects the degree of oxidation (0.47% / s measured in Example 1).

[0081] The rotary divider main disc rotates at a constant speed of 30 rpm, with eight V-shaped sample collection slots spaced evenly apart. The pneumatic diverter valve is controlled by a piezoelectric ceramic drive unit, with a response speed of 5 milliseconds. The sample bottle carousel is equipped with dual mechanical positioning pins to ensure precise alignment of the collection bottles with the diversion path. A key advantage lies in the closed-loop control of the execution process. When the optical detection unit detects an oxidation anomaly, the central controller instantly adjusts the diverter valve opening to isolate the abnormal sample to the waste channel.

[0082] An industrial computer runs a dielectric-mechanical dynamic coupling algorithm and connects to a vector network analyzer via a PCIe bus. A PLC controller uses the PROFINET protocol to connect 64 piezoelectric ceramic drive units, achieving synchronization accuracy of 0.1 microseconds. A data acquisition card captures spectral data at a 1MHz sampling rate and performs noise filtering. These three systems are interconnected via a backplane bus, achieving 100-millisecond response control at every step of the sample preparation process.

[0083] This system features a comprehensive air supply system. 0.6MPa compressed air is distributed across three routes: one route, through the air curtain device at the top of the microwave cavity, creates a 0.5m / s downward airflow to block dust; a second route, connected to the jet ring at the bottom of the crushing tube, maintains a coal suspension density of 0.3g / cm³; and a third route, connected to the optical window self-cleaning nozzle, delivers a 0.1-second pulse of air every 120 seconds. This three-tiered air supply ensures that the core equipment maintains over 95% of its initial performance after 2,000 hours of continuous operation.

[0084] The system's dual-sealed discharge port is located at the end of the system, and the sample collection carousel operates in conjunction with a negative pressure dust removal system. When the carousel's positioning slots align with the collection bottles, the rotary sealing cap mechanism is activated, while a negative pressure tube forms an annular airflow barrier at the bottle opening. This structure effectively isolates the outside air, keeping the oxidation increment of the prepared sample after packaging to 0.3% / hour, far exceeding the 1.0% upper limit stipulated by international standards.

[0085] Example 1: This example uses high-volatile bituminous coal from a certain mining area. Traditional sample preparation has problems such as large moisture control deviation, high crushing energy consumption, and severe oxidation.

[0086] Objective: Prepare 1 mm analytical samples with a moisture control accuracy of ±0.5%, crushing energy consumption ≤12 kWh / t, and oxidation increment ≤0.1% / h.

[0087] The implementation process is as follows:

[0088] Coal sample pretreatment S1: 420 g of raw coal is fed into the waveguide treatment cavity and the stepped frequency conversion microwave is started:

[0089] Initial frequency: 2.45 GHz, 800 W to quickly evaporate surface water; linearly reduced to: 915 MHz, 300 W to remove bound water in 240 seconds.

[0090] The key parameters are:

[0091]

[0092] Dynamic moisture control S2, dielectric analyzer collects data every 10 seconds.

[0093] Measured in seconds: , rad / s, g / cm³

[0094] Calculate the effective moisture value:

[0095]

[0096] Closed-loop regulation: , stop drying immediately. Actual moisture content is 6.9%.

[0097] The acoustic resonance breaks S3, activates the piezoelectric ceramic array, and calculates the resonant frequency:

[0098]

[0099] Determine the duration of the break:

[0100]

[0101] The particle size distribution is concentrated at 1±0.15 mm, accounting for 90%, and the over-crushing rate is only 3.5%.

[0102] Oxidation Monitoring S4, Seconds fluorescence detection: au, au

[0103] Oxidation rate calculation:

[0104]

[0105] Early warning mechanism: The throttling threshold was not triggered.

[0106] Smart reduction S5, using the benchmark reduction ratio:

[0107]

[0108] Sample packaging: Oxidation increment after negative pressure sealing is 0.07% / h.

[0109] Comparative Example 1: This comparative example uses the same high-volatile bituminous coal as in Example 1 to prepare a sample, and is implemented according to a traditional method. The implementation process is as follows:

[0110] The operator spread 500g of raw coal onto an enameled tray and placed it in a 105°C electric forced-air drying oven. The coal was removed and weighed every 30 minutes, and drying was terminated when the difference between two consecutive measurements was less than 0.1%. This process was repeated four times, taking 120 minutes. The final moisture content was 7.2%, with a tolerance of ±1.8%.

[0111] The dried coal sample was crushed to 6 mm in a jaw crusher and then subjected to secondary crushing in a roller crusher. To achieve the target particle size of 1 mm, the roller spacing had to be adjusted three times, resulting in a total crushing time of 15 minutes. Screening after crushing revealed that only 72% of the primary particle size was 1 mm, and the overcrushing rate was <0.1 mm at 15.2%.

[0112] Manual reduction using a cross-section sample plate: The coal pile was mixed in a conical shape, flattened, and then cut into a quarter sample. The sample was exposed to air for 8 minutes. After reduction, it was placed in a wide-mouth bottle and allowed to stand. After 24 hours, the moisture loss was 1.7%, and the volatile matter decreased by 0.9%.

[0113] Differences from Example 1: Real-time moisture monitoring is impossible, and high temperatures result in a volatile matter loss of up to 2.3%. In Example 1, microwave step-by-step frequency conversion takes only 4 minutes and maintains a temperature of ≤65°C. Mechanical extrusion generates significant heat, causing the roller temperature to rise to 80°C, initiating coal sample oxidation. In Example 1, acoustic resonance crushing is contactless and temperature-free, with an over-crushing rate of 3.5%. Manual operation causes coarse particles to roll off the edge of the particle size separation. In Example 1, the pneumatic diverter valve isolates abnormal samples within 0.5 seconds, ensuring complete air isolation.

[0114] Table 1, Comparison of the implementation process of Comparative Example 1 and Example 1

[0115] Implementation Process Comparative Example 1 Example 1 Moisture control Drying time> 2 hours, deviation ±1.8% 4 minutes precise control deviation ±0.2% Crushing process Energy consumption: 24 kWh / t, over-crushing rate: 15.2% Energy consumption: 11.4 kWh / t, over-crushing rate: 3.5% Oxidation protection Exposure for 8 minutes, oxidation increase for 24 hours: 9.6% Fully sealed, 24h oxidation increment 1.7% Sample representativeness The error of particle size separation is > 5% Dynamic reduction ensures particle size distribution consistency error < 1%

[0116] The information obtained from Table 1 includes a comparison of key aspects of the implementation process, specifically the moisture control process, the crushing process, the oxidation protection process, and the sample representativeness process. In terms of moisture control, the traditional method takes more than 2 hours and has a deviation of plus or minus 1.8%, while the method in Example 1 only takes 4 minutes and the deviation is controlled to plus or minus 0.2%. In terms of the crushing process, the traditional method has an energy consumption of 24 kWh per ton and an over-crushing rate of 15.2%. The energy consumption of the method in Example 1 is reduced to 11.4 kWh per ton and the over-crushing rate is only 3.5%. In terms of oxidation protection, the traditional method exposes the sample to air for 8 minutes, resulting in a 24-hour oxidation increase of 9.6%. The method in Example 1 is sealed throughout the process, which controls the oxidation increase to 1.7%. In terms of sample representativeness, the traditional method results in a particle size separation error of more than 5% due to manual operation. The method in Example 1 ensures an error of less than 1% through dynamic reduction. It can be seen that Example 1 significantly improves the moisture control speed, the crushing process is more energy efficient and reduces material waste, the oxidation protection measures effectively reduce the risk of sample degradation, and the sample representativeness error is greatly reduced.

[0117] Table 2, Comparison of indicators between Comparative Example 1 and Example 1

[0118] index Comparative Example 1 Example 1 Improvement Moisture control accuracy ±2.3% ±0.4% 83% 1 mm crushing energy consumption 24 kWh / t 11.4 kWh / t 52% Sample preparation time 45 minutes 12 minutes 73% Oxidation increment 24h 9.6% 1.7% 82% Over-crushing rate 15.2% 3.5% 77%

[0119] The information obtained from Table 2 includes the quantitative values ​​and improvement rates of specific indicators, covering the moisture control accuracy index, 1 mm crushing energy consumption index, sample preparation time index, 24-hour oxidation increment index and over-crushing rate index. In terms of moisture control accuracy index, the deviation of the traditional method is plus or minus 2.3%, while the method of Example 1 improves to plus or minus 0.4%, with an accuracy improvement of 83%. In terms of 1 mm crushing energy consumption index, the traditional method is 24 kWh per ton, while the method of Example 1 is reduced to 11.4 kWh per ton, with an energy consumption reduction of 52%. In terms of sample preparation time index, the traditional method takes 45 minutes, while the method of Example 1 is shortened to 12 minutes, with a time reduction of 73%. In terms of 24-hour oxidation increment index, the traditional method is 9.6%, while the method of Example 1 is reduced to 1.7%, with an increment reduction of 82%. In terms of over-crushing rate index, the traditional method is 15.2%, while the method of Example 1 is reduced to 3.5%, with a reduction of 77%. It can be seen that Example 1 achieves a breakthrough improvement in moisture control accuracy, significantly reduces crushing energy consumption, significantly improves sample preparation efficiency, effectively suppresses oxidation increment, and significantly reduces over-crushing rate.

[0120] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fully automatic coal sampling and analysis method, characterized in that: The following steps are involved: S1. Multi-frequency pretreatment of coal samples: the original coal sample is sent into the microwave treatment chamber and moisture is controlled by step-by-step variable frequency microwave radiation; S2, dynamic moisture closed-loop control: through real-time monitoring of the dielectric properties of coal samples, dynamic calculation of effective moisture value and feedback adjustment of microwave parameters; S3, Acoustic Resonance Precision Crushing: When the coal sample reaches the target moisture range, surface acoustic wave vibrations of a specific frequency are applied to cause the coal sample to self-fragment; S4, optical monitoring of oxidation degree; The ultraviolet LED array is used to detect the surface oxidation state of the coal sample in real time; S5. Intelligent reduction adjustment: Dynamically adjust the reduction ratio based on oxidation monitoring results to prevent sample degradation.

2. The method according to claim 1, wherein The specific process of S1 includes: 200-500g of raw coal sample is placed into the waveguide cavity and microwave frequency is continuously decreased. The treatment process meets the following requirements: ； in, express The microwave frequency at the moment; Represents time parameters; Indicates the maximum operating frequency; Indicates the minimum operating frequency; Indicates the total processing time.

3. The method according to claim 1, wherein The specific process of S2 includes: The dielectric parameters are collected every 10 seconds by a vector network analyzer, the effective moisture value is calculated, and the microwave power is adjusted in real time. The calculation model is: ； in, Indicates the effective moisture value; represents the dielectric-moisture conversion coefficient; represents the dielectric loss factor; represents the microwave angular frequency; Indicates the true density of coal; Indicates the initial value of moisture attenuation; represents the decay rate coefficient; Indicates drying time.

4. The method according to claim 1, wherein The specific process of S3 includes: when The piezoelectric ceramic array is activated at this time, and a resonant crushing wave is generated according to the mechanical properties of the coal body. The frequency calculation formula is: ； in, represents the surface acoustic wave frequency; Indicates the speed of sound wave propagation; Indicates the target granularity; represents the elastic modulus; represents the moisture correction factor; Indicates compressive strength.

5. The method according to claim 4, wherein The duration of the crushing process is determined by the following formula: ； in, Indicates the duration of vibration; Indicates the maximum allowed duration; Indicates the target granularity; Indicates compressive strength; Indicates the effective moisture value; Represents a natural constant.

6. The method according to claim 1, wherein The specific process of S4 includes: Using a 365 nm UV LED array, the degree of oxidation is determined by the fluorescence intensity decay rate: ； in, represents the fluorescence decay rate; represents the initial fluorescence intensity; express Fluorescence intensity at each moment; Indicates the exposure time of coal sample.

7. The method according to claim 1, wherein The specific process of S5 includes: The reduction ratio is dynamically adjusted according to the oxidation rate. The adjustment formula is: ； in, Indicates the actual reduction ratio; Indicates the base reduction ratio; represents the measured fluorescence decay rate.

8. A fully automatic coal sampling and analysis system for implementing the method according to any one of claims 1 to 7, characterized in that: include: The pre-processing unit includes a variable frequency microwave generator, a waveguide processing chamber and a coal sample conveyor belt with a built-in weighing sensor; The core processing unit is a resonant crushing tube wrapped by a piezoelectric ceramic vibration ring, with a dielectric measurement probe embedded in the tube wall; Optical monitoring unit, a fluorescence detection component consisting of a quartz window, a UV LED array, and a spectrum analyzer; The reduction execution unit includes a rotary reducer, a pneumatic diverter valve and a sample bottle turntable; Central control system, integrating industrial computers, data acquisition cards and PLC controllers; Among them, the discharge port of the waveguide processing cavity is connected to the feed end of the resonance crushing tube, the end of the crushing tube is connected to the feed port of the rotary divider, the output end of the dielectric measurement probe and the spectrum analyzer is connected to the industrial computer through the data acquisition card, and the output end of the PLC controller controls the variable frequency microwave generator, piezoelectric ceramic vibration ring and pneumatic diverter valve respectively.

9. The system according to claim 8, wherein: The piezoelectric ceramic vibration ring is made of lead zirconate titanate material.

10. The system according to claim 8, wherein: The surface of the quartz window is coated with a nano-coating that prevents coal dust adhesion.

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