X-ray static CT (Computed Tomography) online coal quality detection method

Abstract

The invention provides an X-ray static CT online coal quality detection method, and relates to the technical field of coal quality detection.The method comprises the steps that the coal flow quality is obtained, and a multi-energy linear attenuation coefficient graph of the coal flow is obtained through a static multi-energy CT scanning technology; on the basis of a set linear attenuation coefficient threshold value, the coal flow pores are judged, a multi-energy linear attenuation coefficient graph with the pores removed is obtained, and the real density of the coal flow is calculated on the basis of the coal flow volume and the coal flow mass with the pores removed; segmenting the multi-energy linear attenuation coefficient graph without pores, averaging each region as a multi-energy linear attenuation coefficient of the region, and calculating a multi-energy mass attenuation coefficient of each region based on the multi-energy linear attenuation coefficient of each region and the real density of the coal flow; and solving based on the multienergy mass attenuation coefficients of different regions and a known multienergy mass attenuation coefficient simultaneous equation set of each element to obtain the mass fraction of each element of the coal flow. By the adoption of the scheme, online measurement of the ash content of the coal flow and the element composition in the coal is achieved.

Description

Technical Field

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

[0002] At present, 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) neutron prompt gamma-ray activation analysis; (4) X-ray fluorescence technology, etc.

[0003] The disadvantages of the existing technologies are as follows: (1) Dual-energy gamma-ray transmission method uses a radioactive source, which is inconvenient to manage. In addition, it is greatly affected by the changes in the elemental composition of the coal and is only suitable for measuring coal from a single mine. (2) X-ray transmission method uses a beam of radiation to transmit the coal flow to measure the ash content. In the calculation model, the transmitted coal flow is regarded as a uniform medium, but the actual coal flow contains particles of different components and is not uniform, so the model will cause errors. (3) Neutron prompt gamma ray activation analysis uses a neutron radiation source, which is more dangerous, requires unchanged management, has a short neutron source half-life, and a short replacement cycle. (4) X-ray fluorescence technology has low radiation energy and weak penetration ability, and cannot analyze thick coal. Summary of the invention

[0004] The present application aims to solve one of the technical problems in the related art at least 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-mentioned purpose, the embodiment of the present application proposes an X-ray static CT online coal quality detection method for online coal quality detection of coal flow on a conveyor belt, the method comprising: 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 removing the porosity; 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.

[0007] Optionally, in one embodiment of the present application, 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:

[0008] 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.

[0009] Optionally, in one embodiment of the present application, 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 of the coal flow are obtained by solving the simultaneous equations, including: For X-rays with energy E, the linear combination of the mass attenuation coefficient of the coal flow is:

[0010] 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:

[0011] 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.

[0012] The X-ray static CT online coal quality detection method of the embodiment of the present application obtains the total mass M of the material, and 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 scanning area, take the average of the linear attenuation coefficients of all grid points in each area, take this as the linear attenuation value representing the entire area, and divide it by the true density to obtain the mass attenuation coefficient of the mixture; solve the average mass attenuation coefficient equation group of different energies in the area to obtain the content of each element in the coal sample.

[0013] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram of a flow chart of an X-ray static CT online coal quality detection method provided in Example 1 of the present application; Figure 2 This is the technical roadmap for X-ray static CT online coal quality detection in the embodiment of the present application. DETAILED DESCRIPTION

[0015] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0016] The following describes the X-ray static CT online coal quality detection method of an embodiment of the present application with reference to the accompanying drawings.

[0017] Figure 1 This is a flow chart of an X-ray static CT online coal quality detection method provided in Example 1 of the present application.

[0018] like Figure 1 As shown, the X-ray static CT online coal quality detection method includes the following steps: Step 101, obtaining the mass of the coal flow, and obtaining a multi-energy linear attenuation coefficient diagram of the coal flow by static multi-energy CT scanning technology; By calculating the product of the material weight per unit length and the belt speed, the instantaneous material flow rate is obtained, and the flow data is integrated to obtain the cumulative amount of the material. The entire process is real-time and non-contact, and will not affect the transportation of materials.

[0019] Static multi-energy CT scanning technology uses X-rays of different energies to penetrate the coal flow, produce different absorptions, and generate linear attenuation coefficient images of the coal flow at different energies. Specifically, for X-rays of a certain energy penetrating the material, the beam intensity changes as follows:

[0020] 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 location [1 / m]; The static CT projection data are reconstructed into the linear attenuation coefficient of each point in the material using the back-projection algorithm, thereby obtaining a linear attenuation coefficient image at a given energy.

[0021] Step 102, based on the set linear attenuation coefficient threshold, the coal flow porosity is determined according to the multi-energy linear attenuation coefficient map, the multi-energy linear attenuation coefficient map without porosity is obtained, and the coal flow real density is calculated based on the coal flow volume and coal flow mass after the porosity is removed; The linear attenuation coefficient of a substance to X-rays can be expressed as:

[0022] is the total cross section; 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 gamma rays of specific energy is related to the density and composition of the medium. The linear attenuation coefficient of pores is very different from that of materials. 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 calculated from the material mass M obtained in the first step. .

[0023] Step 103, segmenting the multi-energy linear attenuation coefficient map except for pores, taking the average value of the multi-energy linear attenuation coefficient in each area as the multi-energy linear attenuation coefficient of the area, and calculating the multi-energy mass attenuation coefficient of each area based on the multi-energy linear attenuation coefficient of each area and the true density of the coal flow; The CT scan area is segmented by threshold value and divided into several areas with different components. The density of coal quality in each area is assumed to be the true density. The linear attenuation coefficients of all grid points in each region are averaged and used as the linear attenuation value representing the entire region. This method reduces the error caused by noise or small density fluctuations by smoothing the data, and simplifies the complexity of solving the equations.

[0024] Step 104 , solving a group of simultaneous equations based on the multi-energy mass attenuation coefficients of different regions and the known multi-energy mass attenuation coefficients of various elements to obtain the mass fractions of various elements in the coal flow.

[0025] For X-rays with energy E, the mass attenuation coefficient of the mixture can be expanded into the following linear combination:

[0026] 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 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; The multi-energy mass attenuation coefficient equations are constructed as follows:

[0027] in, , is the average linear attenuation coefficient in a certain area, is the calculated true density. By using the known mass attenuation coefficients of each element at different energies as equation coefficients, combined with numerical methods such as least squares method or matrix decomposition, the composition of the coal sample can be accurately solved. Based on the elemental composition of the coal, the coal ash content can be further calculated.

[0028] The X-ray static CT online coal quality detection method of the embodiment of the present application is as follows: Figure 2 As shown, the total mass M of the material is obtained; the multi-energy linear attenuation coefficient image of the material is obtained by static multi-energy CT; the image is preliminarily segmented, the pore volume is removed, and the true density is calculated ; Perform threshold segmentation on the CT scanning area, take the average of the linear attenuation coefficients of all grid points in each area, take this as the linear attenuation value representing the entire area, and divide it by the true density to obtain the mass attenuation coefficient of the mixture; solve the average mass attenuation coefficient equation group of different energies in the area to obtain the content of each element in the coal sample.

[0029] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0032] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0033] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned 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 by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0034] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0035] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, 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. If 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.

[0036] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, 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 cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify 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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