X-ray Static CT Online Coal Quality Detection Method

Abstract

The present application provides an online coal quality detection method for X-ray static CT, which relates to the technical field of coal quality detection. Among them, the method includes: obtaining the mass of the coal flow, and obtaining the multi-energy linear attenuation coefficient map of the coal flow through static multi-energy CT scanning technology; based on the set linear attenuation coefficient threshold, judging the pores in the coal flow, obtaining the multi-energy linear attenuation coefficient map of the coal flow excluding pores, and calculating the true density of the coal flow based on the volume of the coal flow excluding pores and the mass of the coal flow; segmenting the multi-energy linear attenuation coefficient map of the coal flow excluding pores, taking the average of each region as the multi-energy linear attenuation coefficient of the region, and calculating the multi-energy mass attenuation coefficient of each region based on the multi-energy linear attenuation coefficient of each region and the true density of the coal flow; solving a system of equations based on the multi-energy mass attenuation coefficients of different regions and the multi-energy mass attenuation coefficients of known elements to obtain the mass fractions of each element in the coal flow. The present application adopting the above solution realizes the online measurement of the ash content of the coal flow and the elemental composition in the coal.

Description

Technical Field

[0001] This application relates to the technical field of coal quality detection, and particularly relates to an X-ray static CT online coal quality detection method. Background Art

[0002] Currently, the online measurement of coal ash and elemental composition mainly relies on the following technologies: (1) Dual-energy gamma-ray transmission method; (2) X-ray transmission method; (3) Prompt gamma-ray activation analysis by neutrons; (4) X-ray fluorescence technology, etc.

[0003] The disadvantages of the existing technologies are as follows: (1) For the dual-energy gamma-ray transmission method, a radiation source is used, which is inconvenient to manage. In addition, it is greatly affected by the change of elemental composition in coal and is only suitable for measuring coal from a single mine site. (2) For the X-ray transmission method, a beam of rays is used to transmit the coal flow to measure the ash content. In the calculation model, the transmitted coal flow is regarded as a homogeneous medium, but in actual coal flow, there are particles of different compositions and it is not uniform. Therefore, this model will bring errors. (3) For prompt gamma-ray activation analysis by neutrons, a neutron radiation source is used, which is more dangerous and inconvenient to manage. The neutron source has a short half-life and a short replacement period. (4) For X-ray fluorescence technology, the ray energy is low and the penetration ability is weak, and it is impossible to analyze thick coal. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems in the related technologies to some extent.

[0005] To this end, the purpose of this application is to propose an X-ray static CT online coal quality detection method, which realizes the online measurement of coal flow ash content and elemental composition in coal.

[0006] To achieve the above object, an embodiment of this application proposes an X-ray static CT online coal quality detection method for online coal quality detection of the coal flow on a conveyor belt. The method includes:

[0007] Obtain the mass of the coal flow, and obtain the multi-energy linear attenuation coefficient map of the coal flow through static multi-energy CT scanning technology;

[0008] Based on the set linear attenuation coefficient threshold, judge the pores of the coal flow according to the multi-energy linear attenuation coefficient map, obtain the multi-energy linear attenuation coefficient map excluding pores, and calculate the true density of the coal flow based on the volume of the coal flow excluding pores and the mass of the coal flow;

[0009] Segment the multi-energy linear attenuation coefficient map excluding pores, take the average value of the multi-energy linear attenuation coefficients in each region as the multi-energy linear attenuation coefficient of the region, and calculate the multi-energy mass attenuation coefficient of each region based on the multi-energy linear attenuation coefficient of each region and the true density of the coal flow;

[0010] Solve the simultaneous equations based on the multi-energy mass attenuation coefficients of different regions and the known multi-energy mass attenuation coefficients of each element to obtain the mass fractions of each element in the coal flow.

[0011] Optionally, in an embodiment of the present application, the static multi-energy CT scanning technology uses X-rays of different energies to penetrate the coal flow, generate different absorptions, generate a multi-energy linear attenuation coefficient map, and generate a linear attenuation coefficient map at a given energy, including:

[0012] For the X-rays of a given energy penetrating the coal flow, the change in the beam intensity is:

[0013]

[0014] Wherein, is the intensity of the X-rays passing through the coal flow, is the intensity of the incident X-rays, is the path The linear attenuation coefficient of the substance at the position, is the path length of the ray passing through the substance;

[0015] Use the back-projection algorithm to reconstruct the static CT projection data into the linear attenuation coefficients of each point in the substance to obtain a linear attenuation coefficient map at a given energy.

[0016] Optionally, in an embodiment of the present application, solve the simultaneous equations based on the multi-energy mass attenuation coefficients of different regions and the known multi-energy mass attenuation coefficients of each element to obtain the mass fractions of each element in the coal flow, including:

[0017] For the X-rays with energy E, the linear combination after expanding the mass attenuation coefficient relationship of the coal flow is:

[0018]

[0019] Wherein, is the mass fraction of the i-th element, is the coal flow density, is the linear attenuation coefficient, is the mass attenuation coefficient of the i-th element;

[0020] Construct a system of multi-energy mass attenuation coefficient equations as:

[0021]

[0022] Wherein, , is the average linear attenuation coefficient of the region , is the true density of the coal flow;

[0023] Using the mass attenuation coefficients of known elements at different energies as the equation coefficients, solve for the elemental composition of the coal flow, and calculate the ash content of the coal flow based on the elemental composition of the coal quantity.

[0024] In the X-ray static CT on-line coal quality detection method according to an embodiment of the present application, the total mass M of the material is obtained, and a multi-energy linear attenuation coefficient image of the material is obtained through static multi-energy CT; the image is preliminarily segmented to remove the pore volume, and the true density is calculated. ; perform threshold segmentation on the CT scanning area, take the average value of the linear attenuation coefficients of all grid points in each area as the linear attenuation value representing the overall area, and divide by the true density to obtain the mass attenuation coefficient of the mixture; solve the system of equations of the average mass attenuation coefficients of different energies in this area to obtain the content of each element in the coal sample.

[0025] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present application. Description of the Drawings

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0027] Figure 1 is a schematic flow chart of an X-ray static CT on-line coal quality detection method provided by Embodiment 1 of the present application;

[0028] Figure 2 is a technical roadmap of the X-ray static CT on-line coal quality detection according to an embodiment of the present application. Detailed Embodiments

[0029] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0030] The X-ray static CT on-line coal quality detection method according to an embodiment of the present application is described below with reference to the drawings.

[0031] Figure 1 is a schematic flow chart of an X-ray static CT on-line coal quality detection method provided by Embodiment 1 of the present application.

[0032] As Figure 1 shown, the X-ray static CT on-line coal quality detection method includes the following steps:

[0033] Step 101: Obtain the quality of the coal flow and generate a multi - energy linear attenuation coefficient map of the coal flow through static multi - energy CT scanning technology;

[0034] Calculate the instantaneous material flow rate by multiplying the material weight per unit length by the belt speed, and perform integral calculation on the flow rate data to obtain the cumulative amount of the material. The whole process is real - time and non - contact, and will not affect the transportation of the material.

[0035] Static multi - energy CT scanning technology uses X - rays with different energies to penetrate the coal flow, resulting in different absorptions, and generates linear attenuation coefficient images of the coal flow at different energies. Specifically, for X - rays with a certain energy penetrating a substance, the change in beam intensity is as follows:

[0036]

[0037] Among them, is the intensity of the X - rays penetrating through the coal flow, is the intensity of the incident X - rays, is the path The linear attenuation coefficient [1 / m] of the substance at the position;

[0038] Use the back - projection algorithm to reconstruct the static CT projection data into the linear attenuation coefficients of each point in the substance, so as to obtain the linear attenuation coefficient image at a given energy.

[0039] Step 102: Based on the set linear attenuation coefficient threshold, judge the pores in the coal flow according to the multi - energy linear attenuation coefficient map, obtain the multi - energy linear attenuation coefficient map excluding pores, and calculate the true density of the coal flow based on the volume of the coal flow after removing pores and the mass of the coal flow;

[0040] The linear attenuation coefficient of a substance to X - rays can be expressed as:

[0041]

[0042] is the total cross - section of the action; is Avogadro's constant; is the mass density of the substance; is the atomic weight of the substance. The linear attenuation coefficient μ of different media for γ - rays with a specific energy is related to the density and composition of the medium. The linear attenuation coefficient of pores is very different from that of the material. Therefore, the pore volume in the image can be removed by setting a threshold to obtain the material volume V, and then the true density of the material can be obtained from the material mass M obtained in the first step .

[0043] Step 103: Divide the multi - energy linear attenuation coefficient map excluding pores, take the average value of the multi - energy linear attenuation coefficient in each region as the multi - energy linear attenuation coefficient of that region, and calculate the multi - energy mass attenuation coefficient of each region based on the multi - energy linear attenuation coefficient of each region and the true density of the coal flow.

[0044] Perform threshold segmentation on the CT scan area and divide it into several regions with different compositions. Assume that the density of the coal quality in the grid of each region is the true density. It is assumed that the density is uniform, and the small changes in the linear attenuation coefficient can be ignored. Take the average value of the linear attenuation coefficients of all grid points in each region as the linear attenuation value representing the whole region. This method reduces the errors caused by noise or small density fluctuations by smoothing the data, and at the same time simplifies the complexity of solving the equations.

[0045] Step 104: Solve the simultaneous equations based on the multi - energy mass attenuation coefficients of different regions and the known multi - energy mass attenuation coefficients of each element to obtain the mass fractions of each element in the coal flow.

[0046] For X - rays with energy E, the relationship of the mass attenuation coefficient of the mixture can be expanded into the following linear combination:

[0047]

[0048] Among them, is the mass fraction of the i - th element, is the density of the coal flow, is the linear attenuation coefficient, is the mass attenuation coefficient of the i - th element. The mass attenuation coefficient is only related to the atomic weight of the element and the X - ray energy, and has nothing to do with the density.

[0049] Construct the multi - energy mass attenuation coefficient equations as:

[0050]

[0051] Among them, , is the average linear attenuation coefficient in a certain region obtained, is the calculated true density. Using the known mass attenuation coefficients of each element at different energies as the equation coefficients and combining numerical methods such as the least - squares method or matrix decomposition, the composition of the coal sample can be accurately solved. According to the elemental composition of the coal, the ash content of the coal is further calculated.

[0052] The X - ray static CT on - line coal quality detection method of the embodiment of the present application, as Figure 2 shown, obtains the total mass M of the material; obtains the multi - energy linear attenuation coefficient image of the material through static multi - energy CT; performs preliminary segmentation on the image, removes the pore volume, and calculates the true density. ; Perform threshold segmentation on the CT scan area, take the average of the linear attenuation coefficients of all grid points within each area, and use this as the linear attenuation value representing the overall area. Divide it by the true density to obtain the mass attenuation coefficient of the mixture. Solve the system of equations for the average mass attenuation coefficients at different energies in this area to obtain the content of each element in the coal sample.

[0053] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0054] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of this application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0055] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a customized logical function or process. The scope of the preferred embodiments of this application includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in the reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of this application belong.

[0056] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, which can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then storing it in a computer memory.

[0057] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0058] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of implementing the above embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0059] In addition, each functional unit in various embodiments of the present application may be integrated into a processing module, may exist separately as individual physical units, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0060] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. An X-ray static CT online coal quality detection method, characterized in that: The method is used to perform online coal quality detection on a coal flow on a conveyor belt, and the method comprises: Obtain the coal flow quality and obtain the multi-energy linear attenuation coefficient map of the coal flow through static multi-energy CT scanning technology; Based on the set linear attenuation coefficient threshold, the coal flow porosity is judged according to the multi-energy linear attenuation coefficient map, the multi-energy linear attenuation coefficient map without porosity is obtained, and the coal flow true density is calculated based on the coal flow volume and coal flow mass after the porosity is removed; The multi-energy linear attenuation coefficient map except for pores is segmented, the multi-energy linear attenuation coefficient in each area is averaged as the multi-energy linear attenuation coefficient of the area, and the multi-energy mass attenuation coefficient of each area is calculated based on the multi-energy linear attenuation coefficient of each area and the true density of the coal flow; Based on the multi-energy mass attenuation coefficients of different regions and the known multi-energy mass attenuation coefficients of each element, the mass fractions of each element in the coal flow are obtained by solving the simultaneous equations.

2. The X-ray static CT online coal quality detection method according to claim 1, characterized in that: The static multi-energy CT scanning technology uses X-rays of different energies to penetrate the coal flow, produce different absorptions, generate a multi-energy linear attenuation coefficient map, and generate a linear attenuation coefficient map at a given energy, including: For a given energy of X-ray penetrating the coal flow, the beam intensity changes as follows: in, is the intensity of X-rays penetrating the coal flow, is the intensity of the incident X-ray, For path The linear attenuation coefficient of the material at the position, is the path length of the ray through the substance; The static CT projection data are reconstructed into the linear attenuation coefficient of each point in the material using the back-projection algorithm, and the linear attenuation coefficient map at a given energy is obtained.

3. The X-ray static CT online coal quality detection method according to claim 2, characterized in that: The multi-energy mass attenuation coefficients based on different regions and the known multi-energy mass attenuation coefficients of each element are solved to obtain the mass fractions of each element in the coal flow, including: For X-rays with energy E, the linear combination of the mass attenuation coefficient of the coal flow is: in, is the mass fraction of the ith element, is the coal flow density, is the linear attenuation coefficient, is the mass attenuation coefficient of the ith element; The multi-energy mass attenuation coefficient equations are constructed as follows: in, , For Region The average linear attenuation coefficient is is the real density of coal flow; The known mass attenuation coefficients of various elements at different energies are used as equation coefficients to solve the elemental composition of the coal flow, and the ash content of the coal flow is calculated based on the elemental composition of the coal.

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