Coal slurry ultrasonic particle size detection system and detection method thereof

Abstract

This invention provides an ultrasonic particle size detection system for coal slurry, comprising: a fixed frame; a coal slurry container; a stirring device; a degassing device; a particle size detection device; a signal generator; and an oscilloscope. This invention also provides a method for ultrasonic particle size detection of coal slurry, comprising the following steps: performing ultrasonic particle size detection on clean water to obtain the attenuation amplitude of the clean water; performing ultrasonic particle size detection on degassed coal slurry to obtain the attenuation amplitude of the coal slurry; calculating the ultrasonic attenuation coefficient of the coal slurry based on the attenuation amplitudes of the clean water and the coal slurry; and using Monte Carlo simulation prediction and particle swarm optimization methods to invert the ultrasonic attenuation coefficient of the coal slurry to obtain the ultrasonic particle size distribution of the coal slurry. This invention systematically realizes coal slurry degassing and particle size detection, fundamentally solving the problems of difficult online detection of coal slurry particle size and bubble interference.

Description

Technical Field

[0001] This invention belongs to the field of coal slurry particle size detection, and in particular relates to a coal slurry ultrasonic particle size detection system and its detection method. Background Technology

[0002] In mineral processing, real-time monitoring of slurry particle size distribution is crucial for optimizing grinding and separation processes. Currently, industrial sites often utilize laboratory-based offline laser diffractometers or image detection.

[0003] Laboratory offline laser diffractometers require manual sampling, dilution, and degassing before laser particle size detection, which results in a long detection cycle and makes it impossible to form an effective closed loop.

[0004] Image detection mainly involves image analysis using high-speed cameras or line scan cameras. Images of slurry particles are captured using backlighting or transmitted light sources, and then the particle size distribution is obtained through edge extraction algorithms. This method is simple in structure and requires no coupling agent, but it has several drawbacks, such as the need for manual dilution of the concentration, susceptibility to bubble interference, frequent window cleaning, sensitivity to particle overlap, the need for complex segmentation algorithms, and high computational cost.

[0005] The two existing detection technologies mentioned above cannot achieve online particle size detection, require manual sampling, degassing, and dilution, and have a long detection cycle. Summary of the Invention

[0006] One object of the present invention is to provide a coal slurry ultrasonic particle size detection system and method, and to provide at least the advantages described below.

[0007] This invention provides an ultrasonic particle size detection system and method for coal slurry, which systematically realizes coal slurry degassing and particle size detection, fundamentally solving the problems of difficulty in online detection of coal slurry particle size and bubble interference.

[0008] The technical solution of the present invention is as follows: The ultrasonic particle size analysis system for coal slurry includes: Fixed frame; A coal slurry container, which is fixed on the fixed frame, and the coal slurry container has a slurry inlet pipe and a first slurry outlet; A stirring device includes a brushless motor fixed on the fixed frame and a stirring blade disposed at the output end of the brushless motor, wherein the output end of the brushless motor extends vertically downward into the coal slurry container. The degassing device has an upwardly inclined first slurry inlet on its side wall, which is connected to the first slurry outlet through a first slurry outlet pipe; an air outlet at the top connected to a vacuum pump; and a second slurry outlet at the bottom. The degassing device is equipped with multiple defoaming structures arranged from top to bottom, and a water pump is installed on the first slurry outlet pipe. A particle size detection device includes a detection container, two pairs of ultrasonic transducers located on both sides of the detection container, and a clamping mechanism disposed below the ultrasonic transducers and fixed on a fixed frame. The top of the detection container has a third slurry outlet and a clean water inlet, and the bottom has a second slurry inlet and a clean water outlet. The second slurry inlet is connected to the second slurry outlet through a second slurry outlet pipe, and the third slurry outlet is connected to the slurry inlet pipe. A circulation ball valve is provided on the second slurry outlet pipe. A signal generator and an oscilloscope are electrically connected to the ultrasonic transducer.

[0009] Preferably, in the aforementioned ultrasonic particle size detection system for coal slurry, The degassing device includes a conical tank with a 45° cone angle, a height of 95mm, a top inner diameter of Φ65mm, and a bottom inner diameter of Φ5mm, and a cover plate fixed to the top of the conical tank by clamps; the cover plate has a diameter of Φ70mm and a thickness of 5mm. The first slurry inlet has an inner diameter of Φ10mm and is inclined horizontally at 15°. The inner diameter of the air outlet is 2.5 mm; The plurality of defoaming structures include a lower honeycomb mesh, an upper honeycomb mesh, and a wire mesh demister located above the first slurry inlet, and a defoaming mesh located below the first slurry inlet; The defoaming mesh is a perforated plate with a pore size of Φ1mm, a diameter of Φ65mm, and a thickness of 3mm; Both the lower honeycomb mesh and the upper honeycomb mesh are hexagonal perforated plates with a diameter of Φ65mm and a thickness of 3mm. The lower honeycomb mesh has a aperture of Φ0.5mm, and the upper honeycomb mesh has a aperture of Φ0.2mm; The wire mesh demister is made of iron wire mesh with a wire diameter of Φ0.1mm, a diameter of Φ65mm, and a thickness of 3mm.

[0010] Preferably, in the aforementioned ultrasonic particle size detection system for coal slurry, The ultrasonic transducer is installed using a transmission type. The ultrasonic transducer has a diameter of Φ16mm, a center frequency of 5MHz, and an effective bandwidth of 3.8MHz. The detection container is a cube structure with a side length of 40mm.

[0011] Preferably, in the aforementioned ultrasonic particle size detection system for coal slurry, The fixed frame is made of aluminum profile with dimensions of 20mm×20mm×R1.5; The fixed frame is 440mm long, 340mm wide, and 520mm high.

[0012] Preferably, in the aforementioned ultrasonic particle size detection system for coal slurry, The coal slurry container is a cylindrical container with an inner diameter of Φ190mm, an outer diameter of Φ200mm, and a height of 250mm. The inner diameter of the slurry inlet pipe and the slurry outlet is 20mm. The coal slurry container is equipped with a baffle plate. The slurry inlet pipe is connected to the slurry tank; The coal slurry container is fixed to the fixing frame by an auxiliary fixing device located on its outer lower side; The auxiliary fixing device includes a horizontal fixing rod located on the coal slurry container, a limiting clip sleeved on the horizontal fixing rod, and a fixing bolt located above the limiting clip. The limiting clip is engaged with the fixing frame below, and the fixing bolt passes through the limiting clip and presses the horizontal fixing rod tightly against the fixing frame.

[0013] Preferably, in the aforementioned ultrasonic particle size detection system for coal slurry, The motor shaft of the brushless motor is connected to the stirring blades via a coupling and a drive shaft. The stirring blade includes a bushing with an inner diameter of Φ15mm, an outer diameter of Φ20mm, and a length of 20mm, and a paddle blade with a length of 65mm and a thickness of 1mm.

[0014] An ultrasonic particle size analysis method for coal slurry includes the following steps: Ultrasonic particle size analysis of clean water is performed to obtain the attenuation amplitude of the clean water. Ultrasonic particle size analysis was performed on the degassed coal slurry to obtain the coal slurry attenuation amplitude. The ultrasonic attenuation coefficient of coal slurry is calculated using Formula 1 based on the attenuation amplitude of the clear water and the attenuation amplitude of the coal slurry.

[0015] Where α is the ultrasonic attenuation coefficient of coal slurry, V1 is the attenuation amplitude in clean water, V2 is the attenuation amplitude in coal slurry, and L is the distance between ultrasonic transducers; The ultrasonic particle size distribution of the coal slurry was obtained by inverting the ultrasonic attenuation coefficient of the coal slurry using Monte Carlo simulation prediction and particle swarm optimization.

[0016] Preferably, in the ultrasonic particle size detection method for coal slurry, the ultrasonic particle size distribution of the coal slurry is obtained by inverting the ultrasonic attenuation coefficient of the coal slurry using Monte Carlo simulation prediction and particle swarm optimization methods, including the following steps: Based on Monte Carlo simulation (MC), the phonon behavior is predicted using Equation 2, and the predicted ultrasonic attenuation coefficient of the coal slurry is calculated using Equation 3, thereby calculating the two-dimensional coefficient matrix A (frequency × diameter). Define phonon events:

[0017] In the formula It is a random number that follows a uniform distribution in the interval [0, 1], P is the ratio of scattering coefficient to silencing coefficient, n is the number of phonon scatterings, L is the free path of the phonon, x is the distance the phonon moves along the X-axis, and y is the distance the phonon moves along the Y-axis. Define the theoretical formula for calculating the ultrasonic attenuation coefficient:

[0018] In the formula It is the number of phonons received by the ultrasonic transducer. is the total number of phonon samples, and L is the distance between transducers; Substitute the initial guessed distribution width K and characteristic diameter D into the RR distribution function, and calculate the theoretical attenuation coefficient vector G using Equation 5, combined with the coefficient matrix. Define the particle size RR distribution function:

[0019] In the formula, K is the distribution width (shape parameter). Where is the characteristic diameter (modal diameter), and D is the diameter of the particle; Define the theoretical ultrasonic attenuation coefficient vector

[0020] In the formula, A is the coefficient matrix and F is the particle size distribution; The root mean square error function RMSE is defined using Equation 6 to compare the experimental and theoretical attenuation coefficient vectors. Define the root mean square error function:

[0021] In the formula, N represents the number of discrete frequencies. Theoretical ultrasonic attenuation coefficient, The experimental ultrasonic attenuation coefficient; Using the Particle Swarm Optimization (PSO) algorithm, the particle size distribution parameters are continuously searched. And K minimize the error function RMSE, and the distribution parameters corresponding to the minimized RMSE are... K and K are the optimal granularity distribution parameters.

[0022] The present invention has the following beneficial effects: It solves the problems of traditional particle size detection methods, such as the need for on-site sampling, the impact of particle sedimentation and air bubbles on particle size detection, long detection cycle, and inability to detect online.

[0023] It features lightweight design, quick-release structure, simple maintenance, and a footprint of <0.15m². 2It can be directly installed on the edge of the slurry pool, significantly improving the accuracy and safety of online particle size monitoring in coal and mineral processing. Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0024] Figure 1 A schematic diagram of an embodiment of the ultrasonic particle size detection system for coal slurry provided by the present invention; Figure 2 A schematic diagram of the structure of a coal slurry container in one embodiment of the ultrasonic particle size detection system for coal slurry provided by the present invention; Figure 3 A schematic diagram of the degassing device in one embodiment of the ultrasonic particle size detection system for coal slurry provided by the present invention; Figure 4 This is a schematic diagram of the particle size detection device in one embodiment of the ultrasonic particle size detection system for coal slurry provided by the present invention. Figure 5 A partial structural schematic diagram of an embodiment of the ultrasonic particle size detection system for coal slurry provided by the present invention; Figure 6 A flowchart of an embodiment of the ultrasonic particle size detection method for coal slurry provided by the present invention; The components include: 1. Fixed frame; 2. Coal slurry container; 21. Slurry inlet pipe; 22. First slurry outlet; 23. Baffle plate; 3. Auxiliary fixing device; 4. Agitator; 41. Brushless motor; 42. Agitator blades; 43. Coupling; 44. Drive shaft; 5. Degassing device; 51. First slurry inlet; 52. Air outlet; 53. Second slurry outlet; 54. Lower honeycomb mesh; 55. Upper honeycomb mesh; 56. 57. Wire mesh demister; 58. Defoaming net; 59. Tank body; 50. Cover plate; 61. Clamp; 62. Particle size detection device; 63. Detection container; 64. Third slurry outlet; 65. Clean water inlet; 66. Second slurry inlet; 67. Clean water outlet; 68. Ultrasonic transducer; 69. Clamping mechanism; 60. Ball valve; 7. Gas supply pipe; 8. Vacuum pump; 9. First slurry outlet pipe; 10. Water pump. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0026] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0027] like Figure 1As shown, the present invention provides an ultrasonic particle size detection system for coal slurry, comprising: (1) Fixed frame 1; (2) The coal slurry container 2 is fixed to the fixed frame 1 by an auxiliary fixing device 3. like Figure 2 As shown, the coal slurry container 2 is composed of a cylindrical container with an inner diameter of Φ190mm, an outer diameter of Φ200mm, and a height of 250mm. This cylindrical container contains a slurry inlet pipe 21 with an inner diameter of Φ20mm and a first slurry outlet 22. The coal slurry container 2 is bolted to a baffle plate 23 to prevent vortex generation during stirring and to avoid gas entrainment. For online monitoring, simply connect the slurry inlet pipe 21 to the slurry tank. The auxiliary fixing device 3 secures the coal slurry container 2 by tightening the fixing rod with bolts, preventing the container from shaking during slurry stirring. (3) A stirring device 4, which includes a brushless motor 41 fixed on the fixed frame 1 and a stirring blade 42 disposed at the output end of the brushless motor 41, wherein the output end of the brushless motor 41 extends vertically downward into the coal slurry container 2. The brushless motor 41 is the active device, and its speed is controlled by changing the duty cycle under a controllable program. The coupling 43 connects the motor shaft and the transmission shaft 44 through the set screw and transmits power, while also having buffering, shock absorption, and overload protection functions. The transmission shaft 44 is used to connect the stirring blade 42 and transmit the motor power to the stirring blade. The stirring blade 42 is composed of a bushing with an inner diameter of Φ15mm, an outer diameter of Φ20mm, and a length of 20mm, and a blade with a length of 65mm and a thickness of 1mm. The brushless motor 41 drives the stirring blade 42 to ensure that the particles in the coal slurry container are suspended and the concentration is uniform, preventing particle sedimentation or agglomeration that could lead to measurement errors.

[0028] (4) Degassing device 5, such as Figure 3 As shown, its sidewall has an upwardly inclined first slurry inlet 51 connected to the first slurry outlet 22 via a first slurry outlet pipe 9, a top has an air outlet 52 connected to a vacuum pump 8 via an air supply pipe 7, and a bottom has a second slurry outlet 53; and the degassing device 5 has multiple defoaming structures arranged from top to bottom, and a water pump 10 is installed on the first slurry outlet pipe 9. The plurality of defoaming structures include a lower honeycomb mesh 54, an upper honeycomb mesh 55 and a wire mesh demister 56 located above the first slurry inlet 51, and a defoaming mesh 57 located below the first slurry inlet 51. The tank 58 is a conical barrel with a 45° cone angle, a height of 95mm, a top inner diameter of Φ65mm, and a bottom inner diameter of Φ5mm. A first inlet 51 with an inner diameter of Φ10mm and a horizontal inclination of 15° is provided on the outer wall of the tank 58. The slurry enters the tank 58 through the first inlet 51. The second outlet 53, with a diameter of Φ5mm at the bottom of the cone, allows the slurry to remain inside the tank 58 for a longer time, which is beneficial for the escape of air bubbles. The defoaming mesh 57 is a perforated plate with a pore size of Φ1mm, a diameter of Φ65mm, and a thickness of 3mm. The defoaming mesh 57 is placed between the first inlet 51 and the second outlet 53. When the slurry flows from the first inlet 51 through the defoaming mesh 57, it can effectively filter air bubbles, achieving gas-liquid separation. The double-layer honeycomb mesh consists of two hexagonal perforated plates with a diameter of Φ65mm and a thickness of 3mm. The lower honeycomb mesh 54 has a pore diameter of Φ0.5mm, and the upper honeycomb mesh 55 has a pore diameter of Φ0.2mm. The bubbles filtered by the defoaming mesh 57 in the slurry rise to the surface due to the negative pressure created inside the tank 58 by the vacuum pump 8. Large bubbles are cut into numerous microbubbles or burst after passing through the lower honeycomb mesh 54. These microbubbles then rise to the surface and are further cut into even smaller bubbles or burst again after passing through the upper honeycomb mesh 55. The wire mesh demister 56 is made of iron wire mesh with a wire diameter of Φ0.1mm, a diameter of Φ65mm, and a thickness of 3mm. It is used to prevent droplets carrying microparticles from being sucked into the vacuum pump 8, which would damage the pump body and prevent pump body corrosion, blockage, and secondary pollution.

[0029] The bubbles that rise after being cut by the upper honeycomb mesh 55 may contain bubble droplets. The intercepted droplets gather into large droplets along the surface of the wire mesh demister 56 and fall back into the tank by gravity, achieving zero discharge and zero loss. The cover plate 59 is a disc with a diameter of 70 mm and a thickness of 5 mm, and has a 2.5 mm vent hole 52 on the top. The cover plate 59 is fixedly connected to the tank body 58 by clamps 50. The cover plate 59 allows for the periodic replacement of the internal components of the tank body 58 and the release of gas from the tank body 58. The vacuum pump 8 connects the air inlet and the air outlet 52 through the air supply pipe 7 to draw away the gas in the tank 58, forming a slight negative pressure lower than atmospheric pressure, and ensuring that the inside of the tank 58 is in a negative pressure state. (5) Particle size detection device 6, such as Figure 4As shown, it includes a detection container 61, two pairs of ultrasonic transducers 62 located on both sides of the detection container 61, and a clamping mechanism 63 disposed below the ultrasonic transducers 62 and fixed on the fixed frame 1. The top of the detection container 61 has a third slurry outlet 611 and a clean water injection outlet 612, and the bottom has a second slurry inlet 613 and a clean water outlet 614. The second slurry inlet 613 is connected to the second slurry outlet 53 through a second slurry outlet pipe. The third slurry outlet 611 is connected to the coal slurry container 2. A ball valve 64 is provided on the second slurry outlet pipe. The ultrasonic transducer 62 has a diameter of Φ16mm, a center frequency of 5MHz, and an effective bandwidth of 3.8MHz (6dB attenuation range). It is installed on both sides of the detection container 61 in a transmission-type (one transmitter and one receiver) manner, perpendicular to the flow direction of the coal slurry. The ball valve 64 is used to prevent backflow of clean water when detecting the attenuation amplitude of clean water; The clamping mechanism 63 consists of a track and a slider, and is used to coaxially and vertically fix the ultrasonic transducer 62 to the outer wall of the detection container 61. The testing container 61 is a cube with a side length of 40mm. The bottom surface has a second slurry inlet 613 equipped with a ball valve 64 and a clean water outlet 614, and the top surface has a third slurry outlet 611 with a clean water inlet 612. Clean water can be injected through the clean water inlet 612, and the ball valve 64 can prevent clean water backflow, ensuring that the testing container 61 is filled with clean water, thereby measuring and correcting the ultrasonic attenuation coefficient of the clean water at irregular intervals.

[0030] (6) A signal generator and an oscilloscope, which are electrically connected to the ultrasonic transducer.

[0031] like Figure 5 As shown, the water pump 10, degassing device 5, and particle size detection device 6 are connected through the first slurry outlet pipe and the second slurry outlet pipe, etc., to introduce the coal slurry in the coal slurry container 2 into the degassing device 5 for gas-liquid separation, and then into the particle size detection device 6 for ultrasonic particle size detection. Finally, the slurry is returned to the coal slurry container 2, thereby achieving slurry recycling.

[0032] When performing offline particle size detection, a circulation device can simulate the coal slurry pipeline transportation effect in a coal preparation plant. The aluminum profile frame consists of 19 aluminum profiles of varying lengths, each measuring 20mm × 20mm × R1.5. The frame is 440mm long, 340mm wide, and 520mm high, with a total floor area of ​​<0.15m². 2 .

[0033] This invention provides a method for ultrasonic particle size detection of coal slurry, comprising the following steps: S1: Connect the signal generator, oscilloscope and ultrasonic transducer, and turn on the signal transmitter and oscilloscope.

[0034] S2: Tighten the ball valve and connect it to the water inlet of the measuring container of the testing device via a water pipe. After the measuring device is filled with clean water, read and record the oscilloscope amplitude. Record 10 data points and take the average value as the amplitude of the clean water. After the measurement is completed, open the drain port of the container to drain the clean water. After draining, open the ball valve and simultaneously close the water inlet and drain port.

[0035] S3: Secure the coal slurry container using an auxiliary fixer.

[0036] S4: Start the mixer to stir the slurry in the coal slurry container. Observe whether the coal slurry generates vortices by adjusting the mixer speed. If vortices are generated, reduce the speed appropriately to prevent the vortex from entraining gas.

[0037] S5: Turn on the water pump and vacuum pump. With the water pump running, the slurry flows into the degassing device through the pipeline. The air bubbles carried by the slurry pass through the defoaming net, double-layer honeycomb net, wire mesh demister, and air outlet of the cover plate and enter the vacuum pump. Then, the gas is discharged from the air outlet of the vacuum pump.

[0038] S6: Record the amplitude of slurry decay. The slurry flows into the particle size detection device after passing through the degassing device. The decay amplitude of the slurry is read and recorded by an oscilloscope. The average value is taken from 10 recorded data.

[0039] S7: After the data recording is complete, turn off the signal generator, oscilloscope, water pump, vacuum pump, and mixer in sequence, and clean the degassing device and coal slurry container in a timely manner.

[0040] S8: Analyze the data and calculate the ultrasonic attenuation coefficient of the slurry.

[0041] S9: The particle size distribution of slurry is obtained by inverting the ultrasonic attenuation coefficient of slurry measured in the experiment using a theoretical model.

[0042] This invention utilizes a particle size detection method based on a particle size detection system. After degassing the slurry using the system, the slurry is then tested to achieve the purpose of detecting the particle size of the coal slurry. The specific steps of the coal slurry particle size detection method are as follows: 1. Setup of the slurry particle size detection system: (1) Assembly of the stirring device: Fix the coupling to the motor shaft and the drive shaft with set screws. Fix the stirring blades to the other end of the drive shaft with set screws, ensuring that the set screws are tightened to prevent slippage. Fix the baffle to the slurry container to prevent vortex generation. Fix the auxiliary fixing device to the aluminum profile frame with bolts to fix the slurry container and ensure that the container will not shake when stirring the slurry.

[0043] (2) Assembly of the degassing device: Install the defoaming net, lower honeycomb net, upper honeycomb net and wire mesh demister into the tank in sequence, and fix the cover plate to the top of the tank with clamps to ensure the correct installation sequence. Connect the hoses to the air inlet of the vacuum pump and the air outlet of the cover plate respectively.

[0044] (3) Assembly of particle size detection device: Connect the ball valve to the detection container, apply coupling agent to the surface of the ultrasonic transducer, and clamp the transducer to the outer wall of the measuring container through the clamping mechanism.

[0045] (4) Assembly of the circulation device: The degassing device and particle size detection device are connected in sequence through pipelines to ensure that each device is fixed in a suitable position.

[0046] 2. Record and analyze coal slurry data: (1) Turn on the signal generator and oscilloscope, close the valve and the drain of the test container, inject clean water through the water inlet of the test container, and record 10 data points at multiple frequencies using the oscilloscope. Take the average value as the water attenuation amplitude at each frequency. Open the drain to empty the water from the test container. Open the ball valve and close the water inlet and drain.

[0047] (2) Ensure that the pipe inlet and outlet in the coal slurry container are at a sufficiently low position on the coal slurry surface to prevent contact with air and thus carry gas into the slurry.

[0048] (3) Turn on the brushless motor button of the stirring device, observe whether eddies are generated with the help of the baffle, and adjust the motor speed to a suitable speed. Record 10 data points at multiple frequencies using an oscilloscope and take the average value as the coal slurry attenuation amplitude at that frequency.

[0049] (4) Organize the corresponding frequency data and calculate the ultrasonic attenuation coefficient of coal slurry using the following formula.

[0050]

[0051] In the formula, α is the ultrasonic attenuation coefficient of coal slurry, V1 is the amplitude measured in clean water, V2 is the amplitude measured in coal slurry, and L is the distance between ultrasonic transducers.

[0052] 3. Coal slurry particle size detection: The particle size distribution of coal slurry can be calculated by combining the ultrasonic attenuation coefficient of coal slurry obtained from experiments with the Monte Carlo (MC) theoretical model and the particle swarm optimization (PSO) algorithm. Figure 6 As shown, it includes the following steps: (1) Start the signal generator and oscilloscope, inject clean water and record the attenuation amplitude of the clean water; (2) Start the system device, record the attenuation amplitude of the coal slurry and calculate the ultrasonic attenuation coefficient of the coal slurry experiment; (3) Based on Monte Carlo simulation (MC), the phonon behavior is predicted using Equation 2, and the predicted ultrasonic attenuation coefficient of coal slurry is calculated using Equation 3, thereby calculating the two-dimensional coefficient matrix A (frequency × diameter). Define phonon events:

[0053] In the formula It is a random number that follows a uniform distribution in the interval [0, 1], P is the ratio of scattering coefficient to silencing coefficient, n is the number of phonon scatterings, L is the free path of the phonon, x is the distance the phonon moves along the X-axis, and y is the distance the phonon moves along the Y-axis. Define the theoretical formula for calculating the ultrasonic attenuation coefficient:

[0054] In the formula It is the number of phonons received by the ultrasonic transducer. is the total number of phonon samples, and L is the distance between transducers; (4) Substitute the initial guessed distribution width K and characteristic diameter D into the RR distribution function, and calculate the theoretical attenuation coefficient vector G by combining the coefficient matrix with formula 5; Define the particle size RR distribution function:

[0055] In the formula, K is the distribution width (shape parameter). Where is the characteristic diameter (modal diameter), and D is the diameter of the particle; Define the theoretical ultrasonic attenuation coefficient vector

[0056] In the formula, A is the coefficient matrix and F is the particle size distribution.

[0057] (5) Define the root mean square error function RMSE for the experimental and theoretical attenuation coefficient vectors using Formula 6. Define the root mean square error function:

[0058] In the formula, N represents the number of discrete frequencies. Theoretical ultrasonic attenuation coefficient, The experimental ultrasonic attenuation coefficient; (6) Using the particle swarm optimization algorithm (PSO), the particle size distribution parameters are continuously searched. And K minimize the error function RMSE, and the distribution parameters corresponding to the minimized RMSE are... K and K are the optimal granularity distribution parameters.

[0059] 4. Subsequent operations: Turn off the signal generator, oscilloscope, water pump, vacuum pump, and mixer in sequence, and clean the degassing device and coal slurry container in a timely manner.

[0060] Precautions: (1) If online particle size detection of coal slurry is to be performed, the slurry inlet pipe of the coal slurry container must be connected to the slurry pool. If offline particle size detection is to be performed, simply pour the slurry into the coal slurry container, and ensure that the coal slurry does not exceed the outlet.

[0061] (2) Regularly inspect all devices and related components of the system to ensure they are in good condition.

[0062] (3) Adjust the speed of the brushless motor according to the baffle and the state of the coal slurry to avoid generating vortices during the stirring process.

[0063] (4) Ensure that each pipe in the coal slurry container is at a sufficiently low position on the surface of the coal slurry.

[0064] The above steps can effectively filter out the gas content in the slurry, thereby reducing the error in coal slurry particle size detection. This provides a theoretical basis for understanding the particle size distribution of slurry in the mineral processing flow, thus optimizing the grinding and separation process.

[0065] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A coal slurry ultrasonic particle size detection system, characterized in that, include: Fixed frame; A coal slurry container, which is fixed on the fixed frame, and the coal slurry container has a slurry inlet pipe and a first slurry outlet; A stirring device includes a brushless motor fixed on the fixed frame and a stirring blade disposed at the output end of the brushless motor, wherein the output end of the brushless motor extends vertically downward into the coal slurry container. The degassing device has an upwardly inclined first slurry inlet on its side wall, which is connected to the first slurry outlet through a first slurry outlet pipe; an air outlet at the top connected to a vacuum pump; and a second slurry outlet at the bottom. The degassing device is equipped with multiple defoaming structures arranged from top to bottom, and a water pump is installed on the first slurry outlet pipe. A particle size detection device includes a detection container, two pairs of ultrasonic transducers located on both sides of the detection container, and a clamping mechanism disposed below the ultrasonic transducers and fixed on a fixed frame. The top of the detection container has a third slurry outlet and a clean water inlet, and the bottom has a second slurry inlet and a clean water outlet. The second slurry inlet is connected to the second slurry outlet through a second slurry outlet pipe, and the third slurry outlet is connected to the slurry inlet pipe. A circulation ball valve is provided on the second slurry outlet pipe. A signal generator and an oscilloscope, which are electrically connected to the ultrasonic transducer; The degassing device includes a conical tank with a 45° cone angle, a height of 95mm, a top inner diameter of Φ65mm, and a bottom inner diameter of Φ5mm, and a cover plate fixed to the top of the conical tank by clamps; the cover plate has a diameter of Φ70mm and a thickness of 5mm. The first slurry inlet has an inner diameter of Φ10mm and is inclined horizontally at 15°. The inner diameter of the air outlet is 2.5 mm; The plurality of defoaming structures include a lower honeycomb mesh, an upper honeycomb mesh, and a wire mesh demister located above the first slurry inlet, and a defoaming mesh located below the first slurry inlet; The defoaming mesh is a perforated plate with a pore size of Φ1mm, a diameter of Φ65mm, and a thickness of 3mm; Both the lower honeycomb mesh and the upper honeycomb mesh are hexagonal perforated plates with a diameter of Φ65mm and a thickness of 3mm. The lower honeycomb mesh has a aperture of Φ0.5mm, and the upper honeycomb mesh has a aperture of Φ0.2mm; The wire mesh demister is made of iron wire mesh with a wire diameter of Φ0.1mm, a diameter of Φ65mm, and a thickness of 3mm.

2. The ultrasonic particle size detection system for coal slurry as described in claim 1, characterized in that, The ultrasonic transducer is installed using a transmission type. The ultrasonic transducer has a diameter of Φ16mm, a center frequency of 5MHz, and an effective bandwidth of 3.8MHz. The detection container is a cube structure with a side length of 40mm.

3. The ultrasonic particle size detection system for coal slurry as described in claim 2, characterized in that, The fixed frame is made of aluminum profile with dimensions of 20mm×20mm×R1.5; The fixed frame is 440mm long, 340mm wide, and 520mm high.

4. The ultrasonic particle size detection system for coal slurry as described in claim 3, characterized in that, The coal slurry container is a cylindrical container with an inner diameter of Φ190mm, an outer diameter of Φ200mm, and a height of 250mm. The inner diameter of the slurry inlet pipe and the slurry outlet is 20mm. The coal slurry container is equipped with a baffle plate. The slurry inlet pipe is connected to the slurry tank; The coal slurry container is fixed to the fixing frame by an auxiliary fixing device located on its outer lower side; The auxiliary fixing device includes a horizontal fixing rod located on the coal slurry container, a limiting clip sleeved on the horizontal fixing rod, and a fixing bolt located above the limiting clip. The limiting clip is engaged with the fixing frame below, and the fixing bolt passes through the limiting clip and presses the horizontal fixing rod tightly against the fixing frame.

5. The ultrasonic particle size detection system for coal slurry as described in claim 4, characterized in that, The motor shaft of the brushless motor is connected to the stirring blades via a coupling and a drive shaft. The stirring blade includes a bushing with an inner diameter of Φ15mm, an outer diameter of Φ20mm, and a length of 20mm, and a paddle blade with a length of 65mm and a thickness of 1mm.

6. A method for ultrasonic particle size detection of coal slurry, applied to the ultrasonic particle size detection system for coal slurry as described in claim 5, characterized in that, Includes the following steps: Ultrasonic particle size analysis of clean water is performed to obtain the attenuation amplitude of the clean water. Ultrasonic particle size analysis was performed on the degassed coal slurry to obtain the coal slurry attenuation amplitude. The ultrasonic attenuation coefficient of coal slurry is calculated using Formula 1 based on the attenuation amplitude of the clear water and the attenuation amplitude of the coal slurry. , Where α is the ultrasonic attenuation coefficient of coal slurry, V1 is the attenuation amplitude in clean water, V2 is the attenuation amplitude in coal slurry, and L is the distance between ultrasonic transducers; The ultrasonic particle size distribution of the coal slurry was obtained by inverting the ultrasonic attenuation coefficient of the coal slurry using Monte Carlo simulation prediction and particle swarm optimization.

7. The ultrasonic particle size detection method for coal slurry as described in claim 6, characterized in that, The ultrasonic particle size distribution of the coal slurry is obtained by inverting the ultrasonic attenuation coefficient using Monte Carlo simulation prediction and particle swarm optimization methods, including the following steps: Based on Monte Carlo simulation (MC), the phonon behavior is predicted using Equation 2, and the predicted ultrasonic attenuation coefficient of the coal slurry is calculated using Equation 3, thereby calculating the two-dimensional coefficient matrix A (frequency × diameter). Define phonon events: ， In the formula It is a random number that follows a uniform distribution in the interval [0, 1], P is the ratio of scattering coefficient to silencing coefficient, n is the number of phonon scatterings, L is the free path of the phonon, x is the distance the phonon moves along the X-axis, and y is the distance the phonon moves along the Y-axis. Define the theoretical formula for calculating the ultrasonic attenuation coefficient: ， In the formula It is the number of phonons received by the ultrasonic transducer. is the total number of phonon samples, and L is the distance between transducers; Substitute the initial guessed distribution width K and characteristic diameter D into the RR distribution function, and calculate the theoretical attenuation coefficient vector G using Equation 5, combined with the coefficient matrix. Define the particle size RR distribution function: ， In the formula, K is the distribution width (shape parameter). Where is the characteristic diameter (modal diameter), and D is the diameter of the particle; Define the theoretical ultrasonic attenuation coefficient vector ， In the formula, A is the coefficient matrix and F is the particle size distribution; The root mean square error function RMSE is defined using Equation 6 to compare the experimental and theoretical attenuation coefficient vectors. Define the root mean square error function: ， In the formula, N represents the number of discrete frequencies. Theoretical ultrasonic attenuation coefficient, The experimental ultrasonic attenuation coefficient; Using the Particle Swarm Optimization (PSO) algorithm, the particle size distribution parameters are continuously searched. And K minimize the error function RMSE, and the distribution parameters corresponding to the minimized RMSE are... K and K are the optimal granularity distribution parameters.

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