A method and system for measuring coal ash components

Abstract

The present invention relates to the technical field of coal ash component determination, and in particular to a method and system for coal ash component determination. The method comprises: performing X-ray diffraction on a coal ash sample to obtain an XRD pattern, detecting the XRD pattern to obtain multiple peak-finding windows; calculating the significance of significant peaks within the peak-finding windows, and using the peak-finding windows with significance levels within the significant interval as characteristic regions; heating the coal ash sample to a first temperature interval to obtain XRD patterns at different temperatures, and determining whether significant peaks within the characteristic region at the same position are overlapping peaks based on the obtained multiple XRD patterns; heating the coal ash sample from the first temperature interval to a second temperature interval to obtain XRD patterns at different temperatures, updating the positions of the peak-finding windows, and further determining the positions of overlapping peaks for coal ash component detection. The present invention takes into account the influence of overlapping peaks when analyzing coal ash components, thereby improving the accuracy of coal ash component analysis results.

Description

Technical Field

[0001] The present invention relates to the technical field of coal ash component determination, and in particular to a method and system for coal ash component determination. Background Art

[0002] Determination of coal ash composition is a crucial step in coal quality testing, with its results directly impacting coal's utility value and environmental protection. Ash composition analysis can reveal the composition of the coal's minerals, indirectly inferring its original mineral composition. Ash component content directly impacts coal's combustion efficiency and utility value, making its mineral composition crucial for quality assessment.

[0003] The Chinese patent application document with publication number CN118671118A discloses a method for determining the content of components in coal ash, including: S1, performing XRF testing on the coal ash to determine the types of elements contained in the coal ash; S2, performing XRD testing on the coal ash to obtain a first XRD spectrum; judging whether the coal ash contains amorphous phase substances based on the first XRD spectrum, if it contains amorphous phase substances, performing XRD testing on a mixture of the internal standard and the coal ash using the internal standard method to obtain a second XRD spectrum, and using the second XRD spectrum as the coal ash XRD spectrum, otherwise, using the first XRD spectrum as the coal ash XRD spectrum; S3, matching the diffraction peaks of the coal ash XRD spectrum in S2 with corresponding compounds based on the types of elements determined in S1 to obtain the types of compounds; S4, processing the coal ash XRD spectrum using the Rietveld / XRD full spectrum fitting method to calculate the relative content of each compound.

[0004] XRD technology is based on Bragg's law. By measuring the diffraction angle and intensity of X-rays in a crystal, the lattice parameters and crystal structure of the crystal can be inferred. The existing technology performs XPF determination on coal ash to determine the type of elements. After that, the coal ash is subjected to two XRD tests. The type of compound is obtained based on the two XRD patterns, and the second image is processed to calculate the relative content of the compound. In the process of using XRD detection to detect the components of coal ash by the existing technology, the peak distance of some compounds is close, and the peak surface of the XRD pattern is prone to overlap. When the existing technology matches the compounds corresponding to the diffraction peaks according to the element types, it does not take into account the peak overlap and cannot distinguish between compounds with similar elements but different crystal structures. Summary of the Invention

[0005] In order to solve the problem that the existing technology does not consider overlapping peaks when detecting coal ash components using XRD detection, resulting in low accuracy of detection results, the present invention provides a method and system for measuring coal ash components.

[0006] In a first aspect, the present invention provides a method for determining coal ash components, which adopts the following technical solution:

[0007] Performing X-ray diffraction on the coal ash sample to obtain an XRD pattern, detecting the XRD pattern to obtain multiple peak search windows, each of which corresponds to a significant peak; calculating the significance of the significant peak in the peak search window, and taking the peak search window with the significance in the significant interval as a characteristic region;

[0008] Heating the coal ash sample to a first temperature interval to obtain XRD patterns at different temperatures, and determining whether significant peaks in a characteristic region at the same position are overlapping peaks based on the obtained multiple XRD patterns;

[0009] The coal ash sample is heated from the first temperature range to the second temperature range to obtain XRD patterns at different temperatures. In response to the number of overlapping peaks in the XRD pattern being greater than a preset threshold, the position of the peak search window is updated to further obtain the position of the overlapping peaks for the detection of coal ash components.

[0010] The coal ash sample is heated to achieve peak separation. Based on the multiple XRD patterns obtained, it is determined whether the corresponding significant peaks are overlapping peaks. Finally, the components in the coal ash sample are analyzed according to the positions of the overlapping peaks in the XRD patterns. The influence of overlapping peaks is taken into account when analyzing the coal ash components, thereby improving the accuracy of the coal ash component analysis results.

[0011] Preferably, the method further comprises: obtaining the first half width and the second half width of the significant peak, and calculating the significance of the significant peak, the expression being:

[0012]

[0013] Where, Indicates the significance of the significant peak in the peak search window A. represents the first half width of a significant peak, represents the second half width of a significant peak, represents the average lateral distance between the peak vertices of the significant peaks in the peak-finding window A, and norm represents the normalization function.

[0014] By calculating the significance of significant peaks, overlapping peaks and potential overlapping peaks can be preliminarily screened out, providing a theoretical basis for subsequent analysis of potential overlapping peaks.

[0015] Preferably, the method further includes: calculating the significance of the characteristic region at the same position in the XRD spectrum at different temperatures; constructing a rectangular coordinate system with temperature as the horizontal coordinate and the significance as the vertical coordinate, mapping the significance of the characteristic region at the same position in multiple XRD spectra into the rectangular coordinate system, fitting the significance to obtain a fitting straight line for the characteristic region at the corresponding position; and constructing a significance sequence using the significance of multiple characteristic regions at the same position.

[0016] Preferably, the method for determining whether the significant peaks in the feature area at the same position are overlapping peaks is: calculating the slope of the fitting line, if the slope is greater than 0, then calculating the change in the significance of the significant peaks in the corresponding feature area, and in response to the significant change being greater than the change threshold, the significant peaks in the feature area are regarded as overlapping peaks.

[0017] The obtained fitting straight line and the slope of the fitting straight line can further reflect how the significance of the significant peak in the characteristic region changes with temperature, making it easier to determine whether the significant peak is an overlapping peak.

[0018] Preferably, the expression of the significant degree change is:

[0019]

[0020] Where, Indicates the change in the significance of the significant peak in the feature region at position B, Indicates the first value in the significance sequence corresponding to the feature region at position B. Indicates the maximum value in the significance sequence corresponding to the feature region at position B.

[0021] By quantifying the change in significance, a basis is provided for judging whether significant peaks are overlapping peaks, thereby improving the accuracy of the judgment results.

[0022] Preferably, the method for calculating the significance change is: obtaining the maximum value in the significance sequence, calculating the mean of the remaining data points in the significance sequence after removing the maximum value, and taking the difference between the maximum value and the mean as the significance change of the significant peak in the corresponding feature area.

[0023] Preferably, the method for determining whether the significant peaks in the characteristic region at the same position are overlapping peaks is as follows: for the significant peaks in the characteristic region at the same position, the distance between any two vertices of the significant peak front is calculated, and the maximum distance is taken as the characteristic value. If the characteristic value of the significant peak is positively correlated with the temperature, then the significant peak is an overlapping peak.

[0024] Whether a significant peak is an overlapping peak is determined by the distance between vertices, which improves the efficiency of the judgment process and enables rapid identification of overlapping peaks.

[0025] Preferably, the XRD pattern is detected using Origin Peak Analyzer software to obtain multiple peak search windows.

[0026] Preferably, before detecting the XRD spectrum, a step of denoising the XRD spectrum is also included.

[0027] In a second aspect, the present invention provides a system for measuring coal ash components, which adopts the following technical solution:

[0028] A system for measuring coal ash components includes: a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned method for measuring coal ash components is implemented.

[0029] The above-mentioned method for determining the composition of coal ash is generated into a computer program and stored in a memory so as to be loaded and executed by a processor. Thus, a system is made based on the memory and the processor for easy use.

[0030] The present invention has the following technical effects:

[0031] The coal ash sample is heated to achieve peak separation. Based on the multiple XRD patterns obtained, it is determined whether the corresponding significant peaks are overlapping peaks. Finally, the components in the coal ash sample are analyzed according to the positions of the overlapping peaks in the XRD patterns. The influence of overlapping peaks is taken into account when analyzing the coal ash components, thereby improving the accuracy of the coal ash component analysis results. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of a method for measuring coal ash components.

[0033] Figure 2 Schematic diagram of the half width of the significant peak of the present invention.

[0034] Figure 3 It is a schematic diagram of the diffraction peak separation state when the coal ash sample of the present invention is heated. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0036] The present invention discloses a method for determining the composition of coal ash. Figure 1 , including the following steps:

[0037] S1: Perform X-ray diffraction on the coal ash sample to obtain an XRD spectrum, and detect the XRD spectrum to obtain multiple peak search windows, each of which corresponds to a significant peak.

[0038] An appropriate amount of coal ash sample is extracted, and the coal ash sample is subjected to X-ray diffraction to obtain an XRD spectrum. The XRD spectrum is denoised and detected using Origin Peak Analyzer software. The Origin Peak Analyzer software generates a peak-finding window during the detection process to identify significant peaks in the XRD spectrum. It can be understood that each peak-finding window corresponds to a significant peak, and the significant peak may be an independent diffraction peak or an overlapping peak composed of multiple diffraction peaks.

[0039] S2: Calculate the significance of the significant peak in the peak-seeking window, and take the peak-seeking window with the significance level in the significant interval as the feature area.

[0040] In the measurement of coal ash components, silicates with different structures may have the same main elements, but different diffraction peak positions. When the diffraction peaks overlap, they appear as overlapping peaks in the XRD spectrum. The overlapping peaks will have an abnormal width, that is, the half-width increases significantly, such as Figure 2 As shown; Based on this principle, the significance of the significant peak is calculated by obtaining the first half width and the second half width of the significant peak, and calculating the significance of the significant peak. The expression is:

[0041]

[0042] Where, Indicates the significance of the significant peak in the peak search window A. represents the first half width of a significant peak, represents the second half width of a significant peak, represents the average lateral distance between the peak vertices of the significant peaks in the peak-finding window A, and norm represents the normalization function, specifically, the Z-score normalization algorithm is used to normalize the average lateral distance.

[0043] It indicates the percentage of increase of the half-width on one side relative to the other side. The larger the value is, the more significant the significant peak in the peak-seeking window A is, that is, the greater the possibility that the significant peak in the peak-seeking window A is an overlapping peak. It represents the average lateral distance between the peak vertices of the significant peaks detected in window A. The larger the distance, the higher the significance of the significant peak in window A. In other words, the significance degree can preliminarily determine the significance of the significant peak, that is, the possibility that the significant peak is an overlapping peak.

[0044] In actual detection, when the significance level is greater than or equal to 0.5, significant peaks are considered overlapping peaks. When the significance level is in the range (0.2, 0.5), the characteristic of significant peaks as overlapping peaks is not obvious enough, and further determination is required. The peak search window where the significance level of significant peaks is in the range (0.2, 0.5) is used as the feature region.

[0045] S3: heating the coal ash sample to a first temperature range, obtaining XRD patterns at different temperatures, and determining whether significant peaks in a characteristic region at the same position are overlapping peaks based on the obtained multiple XRD patterns.

[0046] like Figure 3 As shown in the figure, when the coal ash sample is subjected to temperature variation, the peak surface conditions in a single peak-seeking window will change, and overlapping diffraction peaks will gradually separate. Different types of compounds have concentrated diffraction peaks in different temperature ranges. For example, at 600-900°C, calcite decomposition endothermic peaks. At this time, if the peak-seeking window area corresponding to calcite is an overlapping peak, the overlapping peaks will separate. At 900-1400°C, calcium sulfate decomposes endothermic peaks. If the peak-seeking window area corresponding to calcium sulfate is an overlapping peak, the overlapping peaks will separate.

[0047] That is, when the coal ash sample is subjected to a heat treatment, if the significant peaks in the characteristic region undergo diffraction peak separation, it is highly likely that the significant peaks in the characteristic region are overlapping peaks.

[0048] Exemplarily, the coal ash sample is heated to a first temperature range (600-900°C), and XRD spectra of the coal ash sample at 600°C, 650°C, 700°C, ..., 900°C are obtained respectively, the peak-seeking window in step S1 is locked to each XRD spectrum, and the changes in the significant peaks in the peak-seeking window at the same position are analyzed to determine whether the significant peaks are overlapping peaks, that is, to analyze whether the significant peaks in the characteristic area at the same position are overlapping peaks.

[0049] In one embodiment, a method for determining whether significant peaks within a feature region at the same position are overlapping peaks is as follows:

[0050] S31: Calculate the significance of the characteristic region at the same position in the XRD patterns at different temperatures, construct a rectangular coordinate system with temperature as the horizontal coordinate and significance as the vertical coordinate, map the significance of the characteristic region at the same position in multiple XRD patterns to the rectangular coordinate system, and use the least squares method to fit the significance to obtain a fitting straight line for the characteristic region at the corresponding position.

[0051] For example, the significance of the significant peak in the first characteristic area in the XRD spectrum of the coal ash sample at 600°C, 650°C, 700°C, ..., 900°C is calculated, a rectangular coordinate system is constructed, the significance is mapped to the rectangular coordinate system, and the significance is fitted to obtain a fitting straight line.

[0052] S32: Calculate the slope of the fitting line. If the slope is greater than 0, calculate the change in significance of the significant peak in the corresponding feature area. In response to the significant change being greater than the change threshold, treat the significant peak in the feature area as an overlapping peak.

[0053] The significance degree sequence is constructed using the significance degrees of multiple feature regions at the same position. The expression of the significance degree change is:

[0054]

[0055] Where, Indicates the change in the significance of the significant peak in the feature region at position B, Indicates the first value in the significance sequence corresponding to the feature region at position B. Indicates the maximum value in the significance sequence corresponding to the feature region at position B.

[0056] For example, if the slope of the fitting straight line corresponding to the significance of the significant peak in the first characteristic region is greater than 0, it indicates that as the temperature increases, the greater the change in the significance of the significant peak in the first characteristic region, the greater the possibility that the significant peak in the first characteristic region is an overlapping peak. When the change in significance is greater than the change threshold, the significant peak in the first characteristic region is an overlapping peak. The change threshold is artificially set according to actual conditions, for example, the change threshold is 0.3.

[0057] In one embodiment, the method for determining whether the significant peaks in the characteristic region at the same position are overlapping peaks is as follows: for the significant peaks in the characteristic region at the same position, the distance between any two vertices of the significant peak front is calculated, and the maximum distance is used as the characteristic value. If the characteristic value of the significant peak is positively correlated with the temperature, the significant peak is an overlapping peak.

[0058] For example, at the apex of a characteristic peak's front, the distance between the two endpoints is calculated and used as the characteristic value. During the heating process of a coal ash sample, the heating temperature range is (600-900°C). If the characteristic value of the significant peak within the kth characteristic region increases with increasing temperature, then the significant peak within the kth characteristic region is an overlapping peak. This identification method can quickly identify overlapping peaks and is suitable for scenarios where high accuracy is not a requirement.

[0059] S4: Heat the coal ash sample from the first temperature range to the second temperature range to obtain XRD patterns at different temperatures. In response to the number of overlapping peaks in the XRD pattern being greater than a preset threshold, update the position of the peak search window to further obtain the position of the overlapping peaks for the detection of coal ash components.

[0060] The temperatures at which different components in the coal ash sample react are also different. For example, at 600-900°C, the calcite decomposition endothermic peak is significant, FeS2 is oxidized, and fixed carbon burns. At 900-1400°C, calcium sulfate undergoes an endothermic decomposition reaction, mullite reacts, and the corresponding diffraction peaks will also change.

[0061] For example, the coal ash sample is heated to (900-1400°C) to obtain XRD patterns corresponding to 900°C, 950°C, ..., 1400°C, and the overlapping peaks in the XRD patterns are detected. As the temperature changes, the number of overlapping peaks detected gradually increases. When the number of overlapping peaks reaches a certain value, the original peak-finding window cannot accurately reflect the position of the overlapping peaks. Therefore, the peak-finding window needs to be updated to obtain the updated peak-finding window position, so that the position of the overlapping peak (the position of the overlapping peak in the last XRD pattern) can be obtained. The obtained overlapping peak position is compared with the standard database (PDF card, ICDD) to determine the components in the sample.

[0062] An embodiment of the present invention further discloses a system for measuring coal ash components, including a processor and a memory, wherein the memory stores computer program instructions. When the computer program instructions are executed by the processor, a method for measuring coal ash components according to the present invention is implemented.

[0063] The above system also includes other components well known to those skilled in the art, such as a communication bus and a communication interface. The configuration and functions of these components are known in the art and will not be described in detail here.

[0064] The above are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for measuring coal ash components, characterized in that: Including steps: Performing X-ray diffraction on the coal ash sample to obtain an XRD pattern, detecting the XRD pattern to obtain multiple peak search windows, each of which corresponds to a significant peak; calculating the significance of the significant peak in the peak search window, and taking the peak search window with the significance in the significant interval as a characteristic region; Heating the coal ash sample to a first temperature interval to obtain XRD patterns at different temperatures, and determining whether significant peaks in a characteristic region at the same position are overlapping peaks based on the obtained multiple XRD patterns; heating the coal ash sample from a first temperature range to a second temperature range to obtain XRD patterns at different temperatures, and in response to the number of overlapping peaks in the XRD pattern being greater than a preset number threshold, updating the position of the peak search window to further obtain the position of the overlapping peaks for use in detecting the coal ash components; The method further includes: obtaining the first half width and the second half width of the significant peak, and calculating the significance of the significant peak, the expression is: Where, Indicates the significance of the significant peak in the peak-finding window A. represents the first half width of a significant peak, represents the second half width of a significant peak, represents the average lateral distance between the peak vertices of the significant peaks in the peak-finding window A, and norm represents the normalization function; Calculate the significance of the characteristic region at the same position in the XRD patterns at different temperatures; construct a rectangular coordinate system with temperature as the horizontal axis and significance as the vertical axis, map the significance of the characteristic regions at the same position in multiple XRD patterns to the rectangular coordinate system, and fit the significance to obtain a fitting straight line for the characteristic region at the corresponding position; construct a significance sequence using the significance of multiple characteristic regions at the same position; The method for determining whether the significant peaks in the feature region at the same position are overlapping peaks is as follows: calculating the slope of the fitting line, if the slope is greater than 0, calculating the significance change of the significant peak in the corresponding feature region, and in response to the significant change being greater than a change threshold, the significant peak in the feature region is regarded as an overlapping peak; The expression of the significant change is: Where, Indicates the change in the significance of the significant peak in the feature region at position B, Indicates the first value in the significance sequence corresponding to the feature region at position B. Indicates the maximum value in the significance sequence corresponding to the feature region at position B; The calculation method of the significant change is as follows: obtain the maximum value in the significant sequence, calculate the mean of the remaining data points in the significant sequence after removing the maximum value, and use the difference between the maximum value and the mean as the significant change of the significant peak in the corresponding feature area; The method for determining whether the significant peaks in the characteristic region at the same position are overlapping peaks is as follows: for the significant peaks in the characteristic region at the same position, the distance between any two vertices of the significant peak front is calculated, and the maximum distance is used as the characteristic value. If the characteristic value of the significant peak is positively correlated with the temperature, then the significant peak is an overlapping peak.

2. The method for measuring coal ash components according to claim 1, wherein: The XRD pattern was detected using Origin PeakAnalyzer software to obtain multiple peak search windows.

3. The method for measuring coal ash components according to claim 1, wherein: Before detecting the XRD spectrum, a step of denoising the XRD spectrum is also included.

4. A system for measuring coal ash components, characterized in that: include: A processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, a method for determining coal ash components according to any one of claims 1 to 3 is implemented.

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