Method for coke reactivity after reaction post-integrated optical tissue and pore structure characteristics

Abstract

The present application relates to a kind of coke reaction after strength prediction method of comprehensive optical tissue and pore structure characteristics, comprising:1) optical tissue structure analysis;2) pore structure parameter analysis;3) comprehensive influence analysis and the establishment of CSR prediction formula.The present application uses microcosmic optical tissue structure and pore structure characteristic index to predict CSR, compared with the conventional prediction method using macroscopic index, the workload needed for microcosmic index determination is greatly reduced, thereby reducing the coke oven test operation and response time in field, improve efficiency and reduce cost;In addition, microstructure can essentially reveal the change rule of coke performance, according to the prediction result, coal blending structure can be adjusted, more widely applicable, the prediction result is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal coking, and particularly relates to a method for accurately evaluating coke quality and performance by comprehensively analyzing optical organizational structure and pore structure characteristic parameters. BACKGROUND

[0002] Coke is an important solid fuel obtained by high-temperature dry distillation of coal or other carbonaceous materials in the coking industry, and is widely used in the fields of steel, metallurgy, etc. In the steel smelting process, coke not only serves as a reducing agent and energy source, but also is an important raw material that provides heat and acts as a reaction framework inside the blast furnace. Therefore, the quality of coke directly affects the efficiency of the ironmaking process, product quality, and environmental pollution. Traditional coke quality evaluation methods rely on indicators such as ash content, volatile matter, and elemental composition, but these indicators often cannot comprehensively and accurately reflect the performance of coke in the actual use process, especially under complex conditions of high temperature and high pressure.

[0003] The microscopic organizational features of coke, as important manifestations of its internal structure, can fundamentally reflect the formation process, physical and chemical properties of coke, and its performance in the use process. Microscopic organizational features include the optical organizational structure and pore structure distribution of coke, and these factors have a significant impact on the thermal strength of coke and its combustion process and reaction performance in the furnace. Traditional coke quality evaluation methods mainly rely on macroscopic chemical analysis or mechanical property testing, and cannot reveal the influence of the microscopic structure of coke on its overall performance.

[0004] In recent years, with the rapid development of microscopic detection technology in the field of coal coke, especially the application of high-resolution microscopes and image analysis technology, research on coke quality evaluation based on microscopic organizational features has gradually become a new direction for coke quality control. By carefully observing and analyzing the microscopic organization of coke, its quality characteristics can be more accurately evaluated, and important evidence can be provided for the optimization of the coke production process. In the prior art, coke quality is mainly predicted by the distribution characteristics of its optical organizational structure. However, the structure of coke, especially its microscopic structure, is very complex and extremely uneven, and there is certainly a limitation in predicting coke quality by a single optical organizational distribution characteristic.

[0005] Therefore, there is an urgent need for a coke quality evaluation method based on microscopic organizational features, which introduces modern optical microscopic technology and image processing technology, comprehensively considers the optical organizational structure and pore structure characteristics of coke, and realizes rapid and accurate analysis of the microscopic structure of coke, providing a more scientific and accurate quality evaluation means for the production and application of coke. This not only can improve the control accuracy of the coke production process, but also can improve the performance stability and economy of coke in actual use. SUMMARY

[0006] The application provides a coke post-reaction strength prediction method which comprehensively considers optical organization and pore structure characteristics, and compared with a conventional prediction method using macroscopic indexes, the workload required for microcosmic index determination is greatly reduced, thereby reducing coke oven test operation and response time on site, improving efficiency and reducing cost; in addition, microstructure can essentially reveal the change rule of coke performance, and the coal blending structure can be adjusted according to the prediction result, so that the method has wider applicability and more accurate prediction result.

[0007] In order to achieve the above purpose, the application adopts the following technical scheme:

[0008] A coke post-reaction strength prediction method which comprehensively considers optical organization and pore structure characteristics, comprising the following steps:

[0009] 1) Optical organization structure analysis;

[0010] A plurality of coke samples produced under different sources and different process conditions are selected, and the coke samples are made into coke optical sheets in a cold inlay manner, then a polarized light microscope is used to observe the optical organization characteristics of the coke optical sheets, each organization type is determined by rotating the objective table, and the percentage of each optical component composition is obtained after shooting, so that the proportions of fine-grained inlay organization, medium-grained inlay organization and coarse-grained inlay organization are counted; in addition, the post-reaction strength CSR of the coke sample is detected, and the correlation analysis of the thermal strength of the coke and the CSR is performed;

[0011] 2) Pore structure parameter analysis;

[0012] The gray-scale image of the coke optical sheet is shot by using the polarized light microscope, and the initial image is obtained; then the image is analyzed by using the porosity software, and the pore structure characteristic parameters of the coke sample, including the porosity and the pore size distribution, are obtained; the correlation analysis of the average pore diameter, the average porosity and the CSR of the coke sample is performed;

[0013] 3) Comprehensive influence analysis and establishment of a CSR prediction formula;

[0014] The influence weights of the coke inlay organization content, the average pore diameter and the average porosity on the CSR are calculated based on the CRITIC method, then the weight index is calculated by comprehensively considering the variance and the conflict degree, the weight of each index is standardized, a multiple linear regression model equation is established, and the prediction formula of the CSR is as follows:

[0015] CSR = 28.274 + 0.186X1 + 0.613X2 + 0.201X3

[0016] In the formula, X1 is the proportion of the coke inlay organization, X2 is the average pore diameter, and X3 is the average porosity.

[0017] In the step 1), the polarizing optical microscope parameters are set as: field of view 50x10 times, scanning interval 0.30-0.40 mm, scanning delay 500 ms, focusing frequency 1 s, and at least 200 effective points are photographed.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1) Coke is widely used in the steel, aluminum and other metallurgical industries, and the CSR of coke after reaction is an important indicator for evaluating the quality of coke, which directly affects the smelting efficiency and product quality; by predicting the CSR of coke, metallurgical enterprises can evaluate the quality of coke in advance, thereby optimizing the production process, reducing raw material waste and improving production efficiency.

[0020] 2) Quality control during coke production is the key to improving coke performance; by establishing a CSR prediction model, production enterprises can monitor the quality of coke in real time during coke production and adjust production parameters in a timely manner to ensure the stability and high quality of the final product.

[0021] 3) Accurate prediction of CSR helps optimize the use of coke, avoid excessive consumption of coke that does not meet standards, and helps reduce energy consumption and reduce waste gas emissions, thus having a positive effect on environmental protection.

[0022] 4) The data-based prediction method, combined with intelligent production equipment, can realize the automation optimization of the coke production process, improve production efficiency and reduce labor costs. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a graph of the relationship between the coke reaction strength and the mosaic structure ratio in the present application.

[0024] Figure 2 is a coke pore structure microscopic image before and after processing (Lili coal) in the present application.

[0025] Figure 3 is a coke pore cumulative content graph in the present application.

[0026] Figure 4 is a coke pore distribution graph in the present application.

[0027] Figure 5 is a graph of the relationship between the coke pore structure characteristic parameters and the reaction strength in the present application. DETAILED DESCRIPTION

[0028] The coke post-reaction strength prediction method integrating optical organization and pore structure characteristics provided by the present application evaluates the coke quality by analyzing the microstructure and pore structure parameters of the coke. In order to comprehensively consider the influence of the optical organization structure and the pore structure of the coke on the post-reaction strength CSR, the correlation of the two with the post-reaction strength CSR needs to be determined first, and then the influence of the two on the CSR is comprehensively evaluated. The specific process is as follows:

[0029] (1) Optical organization structure analysis;

[0030] First, coke samples produced under different sources and different process conditions are selected to ensure the representativeness and coverage of the samples. After the coke samples are obtained from the site, the coke optical sheet is made in the cold inlay mode, and then the optical organization characteristics are observed by using the polarized light microscope, and the organization types are determined by rotating the objective table.

[0031] The parameter settings of the polarized light microscope are preferably: field of view 50x10 times, scanning interval 0.30-0.40 mm, scanning delay 500 ms, focusing frequency 1 s. At least 200 effective points are photographed (according to the provisions of “YB / T 077-2017 Coke Optical Organization Determination Method”, cement, pores, cracks and cell structures in the optical organization are regarded as invalid points).

[0032] After the shooting is completed, the percentage of each optical component is obtained, and the proportions of fine-grained inlaid organization, medium-grained inlaid organization and coarse-grained inlaid organization are counted. The above inlaid structure refers to the microstructure of coke, in which semi-coke fragments, isotropic substances and different degrees of coking micro-components are distributed together in an inlaid manner to form a relatively dense microstructure. The research results at the present stage show that the higher the proportion of anisotropic organization, especially the inlaid organization, the higher the coke strength and the better the coke quality.

[0033] The present application selects 20 typical coke samples, detects the proportion of inlaid organization (including fine-grained inlaid organization, medium-grained inlaid organization and coarse-grained inlaid organization) in the optical organization structure, and detects the post-reaction strength CSR at the same time. The results are shown in Table 1:

[0034] Table 1 Proportion of inlaid organization and CSR value of 20 groups of typical coke samples

[0035] Serial number Inlaid weave ratio / % CSR / % 1 7.5 50.5 2 9.5 42.5 3 18.9 57.5 4 20 54.5 5 21.2 61.4 6 40.4 65.4 7 40.5 52.9 8 41.6 63.3 9 44.2 56.5 10 44.5 68.2 11 60.2 63.8 12 61.3 62.5 13 62 61.6 14 65.3 63.8 15 65.7 66.4 16 66.7 60.8 17 69.5 66.4 18 70.3 68 19 77.2 62.3 20 78.1 66.7

[0036] The correlation analysis is performed on the data in Table 1, and the results are shown in Table 2. Figure 1 The correlation coefficient of the hot strength of the coke and the CSR is 0.67, and the variance is 0.525.

[0037] (2) Pore structure parameter analysis;

[0038] The pore structure of coke is one of its important microscopic characteristics. Parameters such as porosity, pore size distribution, and pore shape characteristics of coke have a significant impact on its specific surface area, reactivity, and thermal conductivity.

[0039] Using the aforementioned microscope testing system, grayscale images of coke sections were captured to obtain initial images. Then, the images were analyzed using porosity software to obtain the pore structure characteristics of the coke samples, mainly including porosity and pore size distribution.

[0040] Taking coke from a single type of coal in Lier as an example, the microscopic images of the coke pore structure before and after treatment are as follows: Figure 2 As shown. (Through) Figure 2 After analyzing and obtaining the pore size and pore distribution, we can obtain... Figure 3 The results are shown.

[0041] Current research indicates that coke with smaller, more uniformly distributed pores and smoother pore walls is of better quality. This invention selected 20 groups of typical coking coals and their corresponding cokes for microscopic image analysis, obtaining the average pore diameter and average porosity distribution, as well as the corresponding post-reaction strength (CSR), as shown in Table 2.

[0042] Table 2. Average pore diameter, average porosity, and post-reaction strength of 20 groups of coke.

[0043] Serial number Average pore diameter / pm Average porosity / % CSR 1 20.89 58.21 66.7 2 20.09 60.13 62.3 3 20.73 56.36 68.0 4 23.49 58.99 66.4 5 27.34 65.37 60.8 6 27.49 58.66 66.4 7 29.42 58.35 63.8 8 30.79 58.74 61.6 9 31.42 73.78 62.5 10 33.02 59.77 63.8 11 34.26 59.06 68.2 12 35.36 66.42 56.5 13 36.45 69.48 63.3 14 36.66 65.6 52.9 15 38.95 59.33 65.4 16 40.25 63.62 61.4 17 40.70 68.70 54.5 18 41.41 72.61 57.5 19 41.64 65.88 50.5 20 43.55 67.81 42.5

[0044] As shown in Table 2, the hot strength of coke is inversely proportional to its pore size and porosity. To quantify the influence of coke pore structure, the correlation between the CSR values ​​and pore structure parameters in Table 2 was analyzed, and the results are as follows: Figure 4 As shown, the correlation coefficient between the CSR of coke and the average pore diameter of coke is -0.96, with a variance of 0.907; the correlation coefficient between the CSR of coke and the average porosity is -0.72, with a variance of 0.488.

[0045] (3) Comprehensive impact analysis and establishment of CSR prediction formula;

[0046] To comprehensively consider the influence of coke mosaic structure content, average pore diameter, and average porosity on CSR, the weights of these three factors on CSR are calculated based on the CRITIC method. The calculation process is as follows:

[0047] Mosaic tissue percentage: C1=(1-|r2|)+(1-|r3|)=0.321;

[0048] Average stomatal diameter: C2=(1-|r1|)+(1-|r3|)=0.541;

[0049] Average porosity: C3 = (1 - |r1|) + (1 - |r2|) = 0.310;

[0050] C j (C1, C2, C3) represent the conflict degree of each index, rj represents the correlation coefficient, wherein r1 represents the correlation coefficient of the hot strength of coke and the mosaic structure content, r2 represents the correlation coefficient of the hot strength of coke and the average pore diameter, and r3 represents the correlation coefficient of the hot strength of coke and the average porosity.

[0051] The weight index is calculated by combining the variance and the conflict degree, as shown in formula (1):

[0052]

[0053] In the formula, represents the variance.

[0054] Substituting the calculation can obtain: mosaic structure weight E1 = 0.168, average pore diameter weight E2 = 0.553, and average porosity weight E3 = 0.181.

[0055] The weight of each index is normalized, as shown in formula (2):

[0056]

[0057] The calculation obtains: mosaic structure standard weight W1 = 0.186, average pore diameter standard weight W2 = 0.613, and average porosity standard weight W3 = 0.201.

[0058] Thus, the multiple linear regression model equation is established, as shown in formula (3):

[0059] CSR = k + W1X1 + W2X2 + W3X3 (3)

[0060] In the formula, k is the regression term constant, and k = 28.274; X1 is the proportion of mosaic structure, X2 is the average pore diameter, and X3 is the average porosity.

[0061] Finally, the prediction formula of CSR is obtained, as shown in formula (4):

[0062] CSR = 28.274 + 0.186X1 + 0.613X2 + 0.201X3 (4).

[0063] In order to more directly embody the present application, the embodiments of the present application are further described in conjunction with examples. The following examples are merely the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any skilled in the art can obtain the technical solutions within the technical range disclosed by the present application, including simple changes or equivalent replacements, which are within the protection scope of the present application.

[0064] Example 1

[0065] The process of predicting the coke strength after reaction (CSR) by comprehensively considering the optical texture and pore structure characteristics is as follows:

[0066] (1) Sampling

[0067] Sample source: coke sample used in a 7m top-charged coke oven of a coking plant A.

[0068] Sample specification: particle size range of 30-40mm.

[0069] Sampling amount: 10kg, uniformly mixed and divided into samples, and 3 subsamples were taken.

[0070] (2) Detection

[0071] Coarse grain mosaic texture distribution: characterized by using an optical microscope and image analysis software.

[0072] Average pore diameter, average porosity: determined by combining the volume method and the image analysis method, and the detection results were obtained by using Porosity software, coarse grain mosaic texture distribution: 62%; average pore diameter: 48μm; average porosity: 36%.

[0073] The actual CSR detection result is 62.2%.

[0074] (3) Verification by substituting into the CSR prediction formula

[0075] The data obtained in step (2) are substituted into formula (4), and the calculation result is CSR=62.418%, compared with the actual CSR detection result, the error is 0.218, and the relative error is 0.3%.

[0076] Example 2

[0077] The process of predicting the coke strength after reaction (CSR) by comprehensively considering the optical texture and pore structure characteristics is as follows:

[0078] (1) Sampling

[0079] Sample source: coke sample of a 6m top-charged coke oven of a coking plant B.

[0080] Sample specification: particle size range of 25-35mm.

[0081] Sampling amount: 8 kg, evenly mixed and sampled, 2 sub-samples were taken.

[0082] (2) Detection

[0083] Coarse grain mosaic structure distribution: characterized using an optical microscope and image analysis software.

[0084] Average pore diameter, average porosity: determined by combining the volume method and image analysis method, and the detection results were obtained using Porosity software, coarse grain mosaic structure distribution: 58%; average pore diameter: 52 μm; average porosity: 32%.

[0085] The actual CSR detection result was 75.2%.

[0086] (3) Verification by substituting into the CSR prediction formula

[0087] The calculation result of substituting the data obtained in step (2) into formula (4) was CSR = 77.254%, compared with the actual CSR detection result, the error was 2.054, and the relative error was 2.73%.

[0088] [Example 3]

[0089] The process of predicting the coke strength after reaction (CSR) of this example by comprehensively considering the optical structure and pore structure characteristics is as follows:

[0090] (1) Sampling

[0091] Sample source: 6.25 m stamp-charged coke oven coke sample from a coking plant C.

[0092] Sample specification: particle size range of 30-45 mm.

[0093] Sampling amount: 12 kg, evenly mixed and sampled, 2 sub-samples were taken.

[0094] (2) Detection

[0095] Coarse grain mosaic structure distribution: characterized using an optical microscope and image analysis software.

[0096] Average pore diameter, average porosity: determined by combining the volume method and image analysis method, and the detection results were obtained using Porosity software, coarse grain mosaic structure distribution: 54.1%; average pore diameter: 46 μm; average porosity: 48%.

[0097] The actual CSR detection result was 74.0%.

[0098] (3) Verification by substituting into the CSR prediction formula

[0099] The data obtained in step (2) is substituted into formula (4), and the result is CSR = 76.183%, compared with the actual CSR detection result, the error is 2.183, and the relative error is 2.95%.

[0100] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacements or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method of predicting the strength of coke after reaction with integrated optical tissue and pore structure characteristics, characterized by, It comprises the following steps: 1) optical texture analysis; A plurality of coke samples produced under different sources and different process conditions are selected to make coke optical sections in a cold inlay manner, and then the optical texture characteristics of the coke optical sections are observed using a polarizing optical microscope, each type of organization is determined by rotating the objective table, the percentage of each optical component composition is obtained after shooting, and the proportions of fine-grained inlay organization, medium-grained inlay organization and coarse-grained inlay organization are counted; in addition, the post-reaction strength CSR of the coke sample is detected, and the correlation analysis of the thermal strength and CSR of the coke is performed; 2) pore structure parameter analysis; The gray scale image of the coke optical section is shot using the polarizing optical microscope to obtain an initial image; the image is analyzed using porosity software to obtain the pore structure characteristic parameters of the coke sample, including the porosity and the pore size distribution; the correlation analysis of the average pore diameter, the average porosity and the CSR of the coke sample is performed; 3) comprehensive influence analysis and establishment of a CSR prediction formula; Based on the CRITIC method, the influence weights of the coke inlay organization content, the average pore diameter and the average porosity on the CSR are calculated, the weight index is calculated by comprehensively considering the variance and the conflict degree, the weight of each index is standardized, a multiple linear regression model equation is established, and the prediction formula of the CSR is as follows: CSR = 28.274 + 0.186X1 + 0.613X2 + 0.201X3 In the formula, X1 is the proportion of coke inlay organization, X2 is the average pore diameter, and X3 is the average porosity.

2. The method of predicting the post-reaction strength of coke integrating optical texture and gas pore structure characteristics according to claim 1, characterized in that, In the step 1), the polarizing optical microscope parameters are set as follows: field of view 50x10 times, scanning interval 0.30-0.40 mm, scanning delay 500 ms, focusing frequency 1 s, and at least 200 effective points are shot.

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