Coal reselection monitoring method and system based on selectability index

Abstract

The invention discloses a coal reselection monitoring method and system based on selectability indexes. The method comprises the following steps that an automatic sampling machine is used for conducting real-time sampling on a coal factory entering conveying belt; screening the raw coal sample into a plurality of particle size grades according to the particle size; distributing the particles with different particle sizes obtained by screening, and reserving the number of the particles according to sample representativeness requirements; the weight, the ash content and the density of each particle are measured in real time through a weight sensor, an on-line ash measuring instrument and a density measuring instrument in sequence; summarizing the data of each particle to obtain a comprehensive data table of the density, the yield and the ash content of the coal samples with different particle sizes, and drawing a reselection selectability curve according to the comprehensive data table; the coal gravity separation is carried out according to the selectability parameter, so that the change of the selectability of the coal sample can be judged according to the selectability index, then the coal gravity separation parameter is regulated and controlled in real time, the online control of the gravity separation process according to the change of the property of the coal sample is realized, and the quantity efficiency and the quality efficiency of the gravity separation of a coal preparation plant are further improved.

Description

Technical Field

[0001] The present invention relates to the field of coal preparation, and in particular to a coal re-selection monitoring method and system based on selectivity indicators. Background Art

[0002] With the development of the coal industry and the continuous advancement of science and technology, the intelligent construction of coal preparation plants has become a hot topic. Intelligent coal preparation plants integrate advanced sensor technology, automated control technology, information technology, and artificial intelligence algorithms to achieve real-time monitoring, intelligent decision-making, and automated control of the coal preparation production process, thereby improving production efficiency, reducing costs, and enhancing product quality and stability.

[0003] Coal gravity separation is a commonly used coal separation method in coal preparation plants. It utilizes the density difference between coal and impurities such as gangue to achieve gravity separation, playing a vital role in achieving efficient utilization of coal resources. The coal gravity separation selectivity index reflects the ease of coal separation during the gravity separation process and serves as a key indicator for optimizing gravity separation process parameters and controlling production processes.

[0004] Currently, monitoring coal gravity separation selectivity in coal preparation plants remains challenging. Traditional monitoring methods rely on offline analysis, involving periodic manual sampling of coal for laboratory flotation and sinking tests. This approach is not only time-consuming and labor-intensive, but also fails to reflect real-time changes in the production process. This leads to delayed production adjustments, impacting gravity separation results and product quality stability, and fails to meet the real-time, accurate monitoring data requirements of intelligent coal preparation plants.

[0005] Despite progress in automation and informatization, coal preparation plants have yet to develop a comprehensive intelligent system for real-time monitoring of coal gravity separation selectivity indicators. Existing monitoring equipment and systems often lack effective integration and collaboration, resulting in low levels of data sharing. This prevents them from fully leveraging the advantages of intelligent systems and achieving comprehensive optimization and control of the gravity separation process, hindering the further development of intelligent coal preparation plant development.

[0006] In order to meet the needs of intelligent construction of coal preparation plants, there is an urgent need for a method and system that can monitor the selectivity indicators of coal gravity separation in real time and accurately, so as to make up for the shortcomings of existing technologies and promote the development of coal preparation plants towards a higher level of intelligence. Summary of the Invention

[0007] The present invention aims to address the monitoring lag problem in existing coal gravity separation processes. To this end, the present invention proposes a coal gravity separation monitoring method based on selectivity indicators. This method can effectively achieve real-time and accurate monitoring of coal gravity separation selectivity indicators, providing a reliable basis for optimizing and efficiently operating the coal gravity separation process, and improving the quantitative and qualitative efficiency of coal gravity separation in coal preparation plants.

[0008] The present invention further proposes a coal gravity separation monitoring system based on selectivity index.

[0009] According to an embodiment of the present invention, a coal re-selection monitoring method based on selectivity indicators includes the following steps: real-time sampling using an automatic sampler on a coal conveyor belt entering the plant; screening the raw coal sample into multiple particle size grades according to particle size; distributing the particles of different particle size grades obtained by screening, and retaining the number of particles according to the sample representativeness requirements; measuring the weight, ash content and density of each particle in real time using a weight sensor, an online ash meter and a density meter in turn; summarizing the data of each particle to obtain a comprehensive data table of density, yield and ash content of coal samples of different particle size grades, and drawing a re-selection selectivity curve based on this; and performing coal re-selection according to the selectivity parameters.

[0010] Therefore, by grading the raw coal samples according to the particle size, and by detecting the weight, ash and density of representative particles of the raw coal samples of different particle size grades, a comprehensive data table of the yield, ash and density of samples of different particle size grades is obtained, and then a gravity separation selectivity prediction curve is obtained. This can effectively evaluate the selectivity of the raw coal, realize online control of the gravity separation process, and thus improve the quantity efficiency and quality efficiency of the coal preparation plant's gravity separation, thereby maximizing economic benefits.

[0011] According to some embodiments of the present invention, the step of screening the raw coal sample into multiple particle size grades according to particle size specifically includes: screening the raw coal sample into six particle size grades according to particle size; and removing the raw coal samples in the six particle size grades that do not belong to the gravity selection category.

[0012] According to some embodiments of the present invention, the six particle size classes are the first particle size class A, the second particle size class B, the third particle size class C, the fourth particle size class C, the fifth particle size class E, and the sixth particle size class F. A, B, C, D, E, and F satisfy the relationship: 25 mm < A ≤ 50 mm, 13 mm < B ≤ 25 mm, 6 mm < C ≤ 13 mm, 3 mm < D ≤ 6 mm, 1.0 mm < E ≤ 3 mm, and F ≤ 1.0 mm. The raw coal sample of the sixth particle size class F is removed.

[0013] According to some embodiments of the present invention, the step of screening the raw coal sample into multiple particle size fractions according to particle size further includes: screening the raw coal sample into different particle size fractions through a stacked sieve, and measuring the weight of samples of each particle size fraction using a weight sensor.

[0014] According to some embodiments of the present invention, the step of screening the raw coal sample into different particle sizes through the laminated screen and measuring the weight of the samples of each particle size grade using a weight sensor also includes: after the raw coal samples of each particle size grade flow from the laminated screen to the distribution device for distribution, the number of detection particles is determined according to the particle size of the coal sample, and then the coal particles are sent to different detection lines through a belt conveyor, and then enter the online ash meter to measure the ash, the weight sensor to measure the weight, and the density meter to measure the density to ensure that the number of samples for subsequent detection meets the statistical requirements and the processing capacity of the detection equipment, so that the detection results are more representative.

[0015] According to an embodiment of the present invention, a coal gravity selection monitoring system based on selectivity indicators includes: a coal inlet conveyor belt; an automatic sampler, one end of the automatic sampler is connected to the coal inlet conveyor belt to sample part of the coal on the coal inlet conveyor belt; a laminated screen, the laminated screen is connected to the other end of the automatic sampler to screen the coal samples collected by the automatic sampler into different particle sizes, and each discharge end of the laminated screen is provided with a weight sensor; a distribution device, the distribution device is connected to each discharge end of the laminated screen, and determines the number of detection particles according to the particle size of the coal sample; an online ash meter, the online ash meter is connected to the laminated screen; a weight sensor, the weight sensor is connected to the online ash meter; a density measuring instrument, the density measuring instrument is connected to the weight sensor; a processor, the processor is electrically connected to the weight sensor, the online ash meter and the density measuring instrument respectively; and a controller, the controller is electrically connected to the processor.

[0016] According to some embodiments of the present invention, the density measuring instrument includes a sample chamber, an air pressure sensor and a reference chamber, the sample chamber is connected to the online ash meter, the air pressure sensor is connected to the sample chamber, the sample chamber selectively takes in air, and the sample chamber selectively discharges air to the reference chamber.

[0017] According to some embodiments of the present invention, the density measuring instrument further comprises an air inlet valve and a first air outlet valve, wherein the air inlet valve is arranged at the air inlet of the sample chamber and is selectively opened and closed, and the first air outlet valve is arranged at the air outlet of the sample chamber and is selectively opened and closed.

[0018] According to some embodiments of the present invention, the density measuring instrument further includes a second air outlet valve, which is disposed at the air outlet of the reference chamber and is selectively opened and closed.

[0019] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 is a flow chart of a coal gravity separation monitoring method based on selectivity indicators according to an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a coal gravity separation monitoring system based on selectivity indicators according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of a density measuring instrument according to an embodiment of the present invention.

[0024] Reference numerals:

[0025] 100. Reselection system;

[0026] 10. Coal conveyor belt;

[0027] 20. Automatic sampling machine;

[0028] 30. Laminated screen; 31. Sorting net;

[0029] 40. Online ash meter;

[0030] 50. Density meter; 51. Sample chamber; 52. Air pressure sensor; 53. Reference chamber; 54. Air inlet valve; 55. First air outlet valve; 56. Second air outlet valve; 57. Constant temperature chamber; 58. Online weighing device;

[0031] 60. Fabric device. DETAILED DESCRIPTION

[0032] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0033] Reference below Figure 1 – Figure 3 A coal re-separation monitoring method based on a selectivity index according to an embodiment of the present invention is described. The coal re-separation monitoring method based on a selectivity index can be applied to a coal re-separation monitoring system 100 based on a selectivity index.

[0034] Reference Figure 1 As shown, the coal gravity separation monitoring method based on selectivity index according to an embodiment of the present invention may include the following steps:

[0035] S1, using an automatic sampling machine 20 to take real-time samples on the coal conveyor belt 10;

[0036] S2, screening the raw coal sample into multiple particle size fractions according to particle size;

[0037] S3. Distribute the particles of different particle sizes obtained by screening and retain the number of particles according to the representativeness requirements of the sample;

[0038] S4, measure the weight, ash content and density of each particle in real time by using the weight sensor, online ash meter 40 and density meter 50 in sequence

[0039] S5. Summarize the data of each particle to obtain a comprehensive data table of density, yield and ash content of coal samples of different particle sizes, and draw a gravity separation selectivity curve based on this data;

[0040] S6. Reselect the coal according to the selectivity parameters.

[0041] Specifically, during coal re-selection in a coal preparation plant, an automatic sampler 20 is used on the coal inlet conveyor belt 10 to take real-time samples, and the raw coal samples obtained by sampling are screened into samples of multiple particle sizes according to the particle size. The particles of different particle sizes obtained by screening are distributed, and the number of particles is retained according to the representativeness requirements of the samples. The weight of samples of different particle sizes is tested, and the yield of samples of different particle sizes can be obtained according to the ratio of the weight of samples of different particle sizes to the total weight of the samples.

[0042] Furthermore, ash measurement can be performed on samples of different particle sizes to obtain the ash content of samples of different particle sizes, and the density of samples of different particle sizes can be tested. The signal values ​​of the yield, ash content and density obtained by the test are sent to the processor. The processor summarizes the data of each particle to obtain a comprehensive data table of the density, yield and ash content of coal samples of different particle sizes, and a selectivity prediction curve of coal gravity separation can be drawn based on the comprehensive data table of the yield, density and ash content of samples of different particle sizes.

[0043] It should be noted that the prediction of the re-selection process is a key link in realizing the automation of coal preparation plants. To predict the coal re-selection process, it is necessary to understand the selectivity. The selectivity prediction curve comprehensively describes the distribution pattern of materials with different densities, particle sizes and ash contents in the raw coal. Based on this, the possible results of the raw coal re-selection separation can be analyzed, including the quantity and quality indicators of coal with different particle sizes.

[0044] Therefore, the coal gravity selection monitoring system 100 based on selectivity index can utilize the coal gravity selection monitoring method based on selectivity index of the embodiment of the present invention, and perform online control of coal selection according to the selectivity prediction curve of coal gravity selection, thereby improving the quantity efficiency and quality efficiency of coal selection in the coal preparation plant and maximizing economic benefits.

[0045] Therefore, by grading the raw coal samples according to the particle size, and by detecting the weight, ash and density of representative particles of the raw coal samples of different particle size grades, a comprehensive data table of the yield, ash and density of samples of different particle size grades is obtained, and then a gravity separation selectivity prediction curve is obtained. This can effectively evaluate the selectivity of the raw coal, realize online control of the gravity separation process, and thus improve the quantity efficiency and quality efficiency of the coal preparation plant's gravity separation, thereby maximizing economic benefits.

[0046] In some embodiments of the present invention, step S2 specifically includes:

[0047] The raw coal samples were sieved into six particle size fractions according to particle size;

[0048] Remove the raw coal samples that do not fall within the scope of gravity separation in the six particle size classes.

[0049] Specifically, by screening the raw coal samples into six particle size grades according to particle size, and removing the smaller raw coal samples in the six particle size grades that do not belong to the gravity separation category, not only can the workload of subsequent testing of the weight, density and ash content of raw coal samples of different particle size grades be reduced and the difficulty of testing be reduced, but it can also prevent the raw coal samples that do not belong to the gravity separation category from affecting the detection of raw coal samples that normally belong to the gravity separation category, thereby affecting the drawing results of the gravity separation selectivity prediction curve. This can further improve the reliability of the coal gravity separation monitoring method based on selectivity indicators.

[0050] In some embodiments of the present invention, the six particle size classes are the first particle size class A, the second particle size class B, the third particle size class C, the fourth particle size class C, the fifth particle size class E, and the sixth particle size class F. A, B, C, D, E, and F satisfy the relationship: 25 mm < A ≤ 50 mm, 13 mm < B ≤ 25 mm, 6 mm < C ≤ 13 mm, 3 mm < D ≤ 6 mm, 1 mm < E ≤ 3 mm, F ≤ 1 mm, remove the raw coal samples of the sixth particle size grade F, and divide the raw coal samples into six particle size grades. In this way, the screening of the raw coal samples can be uniform and reasonable. It can not only prevent the particle size grades of the raw coal samples from being screened too much, resulting in a smaller particle size gap between raw coal samples of different particle size grades, resulting in a smaller gap in the test results of raw coal samples of different particle size grades, resulting in the inability to normally draw the gravity separation selectivity prediction curve, but also prevent the particle size grades of the raw coal samples from being screened too little, resulting in a larger particle size gap between raw coal samples, resulting in unreliable gravity separation selectivity prediction curve drawn at last, which can further improve the accuracy and reliability of the gravity separation selectivity prediction curve.

[0051] In some embodiments of the present invention, the step of screening the raw coal sample into multiple particle size fractions according to particle size further includes: screening the raw coal sample into different particle size fractions by a stacked screen 30, and measuring the weight of samples of each particle size fraction by a weight sensor.

[0052] Specifically, the raw coal sample is screened by the laminated screen 30 and is screened into multiple particle size grades. This not only improves the stability and reliability of screening the raw coal sample, but also makes screening simpler and simplifies the structural design.

[0053] Furthermore, by directly setting the weight sensor on the laminated screen 30, after the laminated screen 30 screens the raw coal sample, the weight of the raw coal sample of the corresponding particle size grade can be directly detected by the weight sensor. This not only improves the compactness and integration of the structure, but also makes the detection of raw coal samples of different particle size grades more accurate and rapid, and can improve the reliability of the coal gravity selection method.

[0054] In some embodiments of the present invention, after the steps of screening the raw coal sample into different particle size fractions by the stacked screen 30 and measuring the weight of the samples of each particle size fraction by using a weight sensor, the following steps are further included:

[0055] After the raw coal samples of each particle size grade flow from the laminated screen 30 to the distribution device 60 for distribution, the number of test particles is determined according to the particle size of the coal sample, and then the coal particles are sent to different test lines through a belt conveyor, and then enter the online ash meter 40 for ash measurement, the weight sensor for weight measurement, and the density meter 50 for density measurement.

[0056] It should be noted that after the laminated screen 30 screens the raw coal sample into multiple particle sizes and the weight sensor detects the weight of the raw coal samples of multiple particle sizes, the raw coal samples of multiple particle sizes can be distributed through the distribution device 60 and then enter the online ash meter 40 for ash measurement in turn. This can make the coal re-selection method more stable and prevent raw coal samples of different particle sizes from interfering or even re-mixing when they come out of the laminated screen 30 and enter the online ash meter 40 for ash measurement, thereby improving the stability and reliability of ash measurement and subsequent density measurement.

[0057] Furthermore, after the step of screening the raw coal sample into different particle sizes through the laminated screen 30 and measuring the weight of the samples of each particle size grade using a weight sensor, the step also includes: after the raw coal samples of each particle size grade flow from the laminated screen 30 to the distribution device 60 for distribution, the number of test particles is determined according to the particle size of the coal sample, and then the coal particles are sent to different test lines through a belt conveyor, and then enter the online ash meter 40 to measure the ash, the weight sensor to measure the weight, and the density meter 50 to measure the density to ensure that the number of samples for subsequent testing meets the statistical requirements and the processing capacity of the testing equipment, so that the test results are more representative.

[0058] Reference Figure 2 and Figure 3 As shown, the coal gravity selection system 100 according to an embodiment of the present invention may include: a coal inlet conveyor belt 10, an automatic sampler 20, a laminated screen 30, an online ash meter 40, a density meter 50, a processor and a controller, wherein one end of the automatic sampler 20 is connected to the coal inlet conveyor belt 10 to sample part of the coal on the coal inlet conveyor belt 10, the laminated screen 30 is connected to the other end of the automatic sampler 20 to screen the coal sample sampled by the automatic sampler 20 into different particle size grades, and a weight sensor is provided on the laminated screen 30; the online ash meter 40 is connected to the laminated screen 30, and the density meter 50 is connected to the online ash meter 40; the processor is electrically connected to the weight sensor, the online ash meter 40, the density meter 50 and the coal inlet conveyor belt 10 respectively; and the controller is electrically connected to the processor.

[0059] Specifically, when the coal preparation plant is conducting re-selection, the raw coal material first needs to pass through the coal inlet conveyor belt 10 for re-selection workshop. By connecting the automatic sampler 20 to the coal inlet conveyor belt 10, one end of the automatic sampler 20 can be connected to the coal inlet conveyor belt 10 for collecting, so that the automatic sampler 20 can collect part of the raw coal material on the coal inlet conveyor belt 10 as a raw coal sample. The laminated screen 30 is connected to the other end of the automatic sampler 20. The raw coal sample collected by the automatic sampler 20 can enter the laminated screen 30 for screening. The laminated screen 30 has multiple sorting nets set at intervals, and multiple sorting nets are provided with sorting holes. The aperture of the sorting holes on different sorting nets is different. According to the sorting holes with different apertures on different sorting nets, the raw coal samples can be screened into samples of different particle size grades, and the weight sensors on the laminated screen 30 can detect the weights of samples of different particle size grades respectively.

[0060] Furthermore, after the laminated screen 30 screens the raw coal sample into samples of different particle sizes, the online ash meter 40 can be connected to the laminated screen 30, and the online ash meter 40 can measure the ash of samples of different particle sizes, thereby obtaining the ash content of samples of different particle sizes.

[0061] It should be noted that the ash content of coal refers to the solid residue left after the coal is completely burned. It is mainly composed of incombustible substances formed after the minerals in the coal are burned at high temperature. Ash content is one of the important indicators for evaluating coal quality.

[0062] In some embodiments of the present invention, X-rays can penetrate matter and interact with it to produce specific signals that can be used to analyze the composition of the matter. Given the differences in radiation absorption by elements in coal and gangue, the online ash meter 40 can utilize X-rays to measure the ash content of the coal.

[0063] Furthermore, after the online ash meter 40 measures the ash of samples of different particle sizes, the samples of different particle sizes can enter the density meter 50 for density measurement.

[0064] Furthermore, since the processor is electrically connected to the weight sensor, the online ash meter 40 and the density meter 50 respectively, the processor can process the weight detected by the weight sensor, the ash content detected by the online ash meter 40 and the density detected by the density meter 50, thereby obtaining a comprehensive data table of different particle sizes, and then draw a gravity separation selectivity prediction curve based on the comprehensive data table. The controller is electrically connected to the processor, and the controller can control the gravity separation of coal in the coal preparation plant according to the gravity separation selectivity prediction curve, thereby improving the quantity efficiency and quality efficiency of the coal separation in the coal preparation plant, and further improving the economic benefits of the coal preparation plant.

[0065] Combine Figure 2As shown, the density measuring instrument includes a sample chamber 51, an air pressure sensor 52 and a reference chamber 53. The sample chamber 51 is connected to the online ash meter 40, and the air pressure sensor 52 is connected to the sample chamber 51. The sample chamber 51 selectively takes in air, and the sample chamber 51 selectively discharges air to the reference chamber 53.

[0066] It can be understood that density is the ratio of weight to volume. Since the weights of raw coal samples of different particle sizes have been detected, when measuring the density of raw coal samples of different particle sizes, it is only necessary to measure the volume of raw coal samples of different particle sizes. The density of raw coal samples of different particle sizes can be calculated using the formula between density, weight and volume.

[0067] This embodiment of the present invention applies Boyle's law and the gas displacement method, which uses the principle that the product of the pressure and volume of an equal amount of gas at a constant temperature is a constant value, namely, PV = nRT. The gas displacement method measures the volume displaced by the sample as the gas replaces the liquid. The true volume of the sample is accurately determined by measuring the decrease in gas volume within sample chamber 51 caused by the sample being placed in chamber 51. True density is calculated by dividing mass by true volume.

[0068] The specific operation steps are as follows: any one of the raw coal samples of different particle sizes is placed in the sample bin 51, the sample bin 51 is sealed, air is introduced into the sample bin 51, and the air pressure sensor 52 is connected to the sample bin 51 to measure the air pressure in the sample bin 51. After the air pressure in the sample bin 51 is balanced, the air pressure P1 displayed on the air pressure sensor 52 is recorded. Then, the sample bin 51 is connected to the reference bin 53, and after the air pressure in the sample bin 51 is balanced again, the air pressure P2 displayed on the air pressure sensor 52 is recorded. The volume of any one of the raw coal samples of different particle sizes is set to V. When the volume V1 in the sample bin 51 and the volume V2 in the reference bin 53 are known, the sample volume V can be calculated according to Boyle's law. P0, P1, P2, V1, V2 and V satisfy the relationship: , where P0 is the atmospheric pressure.

[0069] In some specific embodiments of the present invention, the online weigher 58 can also be set in the sample bin 51. This not only prevents the loss of the raw coal sample in the process from the laminated screen 30 to the sample bin 51, but also causes the weight of the raw coal sample in the sample bin 51 to be the weight before the loss, but the volume to be the volume after the loss, resulting in the measured density of the raw coal sample to be inaccurate. By setting the online weigher 58 in the sample bin 51, the weight of the raw coal sample in the sample bin 51 can be detected, and the ratio of weight to volume can be made more accurate, that is, the density measurement can be made more accurate.

[0070] It should be noted that in order to prevent the influence of temperature on pressure, the sample chamber 51, the air pressure sensor 52 and the reference chamber 53 can all be set in a constant temperature box 57, so that the air pressure sensor 52 will not be affected by temperature during the process of measuring air pressure, which can improve the accuracy and reliability of air pressure detection by the air pressure sensor 52.

[0071] Combine Figure 2 As shown, the density measuring instrument further includes an air inlet valve 54 and a first air outlet valve 55. The air inlet valve 54 is disposed at the air inlet of the sample chamber 51 and is selectively opened and closed, while the first air outlet valve 55 is disposed at the air outlet of the sample chamber 51 and is selectively opened and closed. Specifically, by disposing the air inlet valve 54 at the air inlet of the sample chamber 51 and disposing the first air outlet valve 55 at the air outlet of the sample chamber 51, when the sample chamber 51 needs to take in air, the air inlet valve 54 can be opened, thereby improving the stability and reliability of the air intake of the sample chamber 51. When the sample chamber 51 needs to be connected to the reference chamber 53, the first air outlet valve 55 can be opened, thereby improving the stability and reliability of the connection between the sample chamber 51 and the reference chamber 53.

[0072] Combine Figure 2 As shown, the real-time monitoring system for coal gravity separation further includes a second gas outlet valve 56, which is disposed at the gas outlet of the reference bin 53 and is selectively opened and closed. Specifically, by disposing the second gas outlet valve 56 at the gas outlet of the reference bin 53, after the sample bin 51 and the reference bin 53 are connected, and the air pressure in the sample bin 51 is re-equilibrated and the air pressure P2 displayed on the air pressure sensor 52 is recorded, the second gas outlet valve 56 can be opened, thereby deflating the sample bin 51 and the reference bin 53, thereby facilitating subsequent density testing of samples of other particle size fractions among the raw coal samples of multiple particle size fractions.

[0073] Combine Figure 2 As shown, the real-time monitoring system 100 for coal gravity separation further includes a distribution device 60, one end of which is connected to the laminated screen 30, and the other end of which is connected to the online ash meter 40. Specifically, by connecting one end of the distribution device 60 to the laminated screen 30 and the other end of the distribution device 60 to the online ash meter 40, the distribution device 60 can adjust the distribution angle, speed, or amplitude of raw coal samples of multiple particle sizes, thereby avoiding uneven distribution of the coal flow in width or thickness, reducing edge effects or center accumulation, and further improving the stability and reliability of the coal gravity separation system 100.

[0074] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0075] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0076] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A coal gravity separation monitoring method based on selectivity index, characterized in that: The following steps are involved: Use automatic sampling machines to take real-time samples on the coal conveyor belt entering the plant; The raw coal sample is sieved into multiple particle size fractions according to particle size; Distribute the particles of different particle sizes obtained by screening and retain the number of particles according to the representativeness requirements of the sample; The weight, ash content and density of each particle are measured in real time by a weight sensor, an online ash meter and a density meter in sequence; Summarize the data of each particle to obtain a comprehensive data table of density, yield and ash content of coal samples of different particle sizes, and draw the gravity separation selectivity curve based on it; Coal re-selection based on selectivity parameters.

2. The coal gravity separation monitoring method based on selectivity index according to claim 1, characterized in that: The step of screening the raw coal sample into multiple particle size grades according to particle size specifically includes: The raw coal samples were sieved into six particle size fractions according to particle size; The raw coal samples that do not fall within the scope of gravity separation in the six particle size classes are removed.

3. The coal gravity separation monitoring method based on selectivity index according to claim 2, characterized in that: The six particle size classes are the first particle size class A, the second particle size class B, the third particle size class C, the fourth particle size class C, the fifth particle size class E, and the sixth particle size class F. A, B, C, D, E, and F satisfy the relationship: 25 mm < A ≤ 50 mm, 13 mm < B ≤ 25 mm, 6 mm < C ≤ 13 mm, 3 mm < D ≤ 6 mm, 1.0 mm < E ≤ 3 mm, and F ≤ 1.0 mm. The raw coal sample of the sixth particle size class F is removed.

4. The coal gravity separation monitoring method based on selectivity index according to claim 1, characterized in that: The step of screening the raw coal sample into multiple particle size grades according to particle size also includes: The raw coal samples are screened into different particle sizes by using a stacked sieve, and the weight of samples of each particle size grade is measured using a weight sensor.

5. The coal gravity separation monitoring method based on selectivity index according to claim 4 is characterized in that: After the steps of screening the raw coal sample into different particle size grades by the stacked sieve and measuring the weight of the samples of each particle size grade by the weight sensor, the method further comprises: After the raw coal samples of each particle size grade flow from the laminated screen to the distribution device for distribution, the number of test particles is determined according to the particle size of the coal sample. The coal particles are then sent to different test lines through a belt conveyor, and then enter the online ash meter for ash measurement, the weight sensor for weight measurement, and the density meter for density measurement.

6. A coal gravity separation monitoring system based on selectivity index, applicable to the coal gravity separation monitoring method based on selectivity index according to any one of claims 1 to 5, characterized in that: include: Coal inlet conveyor belt; An automatic sampler, one end of which is connected to the coal inlet conveyor belt to sample part of the coal on the coal inlet conveyor belt; A laminated screen, the laminated screen being connected to the other end of the automatic sampler to screen the coal sample collected by the automatic sampler into different particle size fractions, and each discharge end of the laminated screen being provided with a weight sensor; A distribution device, which is connected to each discharge end of the laminated screen and determines the number of particles to be tested according to the particle size of the coal sample; an online ash meter, the online ash meter being in communication with the laminated screen; A weight sensor, the weight sensor being connected to the online ash meter; a density measuring instrument, the density measuring instrument being in communication with the weight sensor; a processor, the processor being electrically connected to the weight sensor, the online ash meter, and the density meter respectively; A controller is electrically connected to the processor.

7. The coal gravity separation monitoring system based on selectivity index according to claim 6, characterized in that: The density measuring instrument includes a sample chamber, an air pressure sensor and a reference chamber. The sample chamber is connected to the online ash meter, the air pressure sensor is connected to the sample chamber, the sample chamber selectively takes in air, and the sample chamber selectively discharges air to the reference chamber.

8. The coal gravity separation monitoring system based on selectivity index according to claim 7 is characterized in that: The density measuring instrument further includes an air inlet valve and a first air outlet valve. The air inlet valve is provided at the air inlet of the sample chamber and is selectively opened and closed. The first air outlet valve is provided at the air outlet of the sample chamber and is selectively opened and closed.

9. The coal gravity separation monitoring system based on selectivity index according to claim 7, characterized in that: The density measuring instrument further includes a second air outlet valve, which is arranged at the air outlet of the reference chamber and is selectively opened and closed.

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