Pore Structure Characteristics and Evolution Law of Different-Rank Coal Samples

Wen, Zhihui; Wang, Qi; Yang, Yunpeng; Si, Leilei

doi:10.1155/2021/1505306

Cited by 8 publications

(5 citation statements)

References 18 publications

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“…On this basis, the values are further calculated, as shown in Table . With the increase of metamorphism, the SSA and pore volume of coal first decreased and then increased at each stage, which is consistent with the conclusions of many literatures. ,, For the GHST sample, the pore volume and SSA showed maximum values within the micropores, but the results of the GHSI sample with the same anthracite were small. The reason for this is the pore structure complexity of anthracite, and LP-ArGA may not be able to characterize the micropores accurately.…”

Section: Resultssupporting

confidence: 91%

Study on Multifractal of Coal Pore Structure Based on Low Pressure Argon Adsorption and Its Effect on Gas Adsorption/Desorption

Wang

Hao

et al. 2023

Energy Fuels

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Although the coal pore structure is attracting the attention of researchers, studies on the multifractal and gas adsorption/desorption capacity are relatively few. In this study, multifractal characteristics were analyzed, and their effects on gas adsorption/desorption were discussed. The results showed that metamorphism and tectonism affected gas adsorption/desorption by changing the coal pore structure. The limit gas adsorption volume and initial desorption rate of tectonic coals increased by 3.9%–23.9% and 1.96–2.7 times, respectively. The information dimension (D 1), correlation dimension (D 2), and classical Hurst index gradually decreased with metamorphism and tectonism, while the Hausdorff dimension and Δα gradually increased, indicating that pore size distribution (PSD) was more decentralized or inhomogeneous. The evaluation results of the correlation between multifractal parameters and complexity confirmed its accuracy in assessing pore complexity. Multifractal parameters have a significant impact on gas adsorption/desorption capacity overall, mainly by reflecting the concentration degree, local density, and homogeneity of pores.

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Section: Resultssupporting

confidence: 91%

Study on Multifractal of Coal Pore Structure Based on Low Pressure Argon Adsorption and Its Effect on Gas Adsorption/Desorption

Wang

Hao

et al. 2023

Energy Fuels

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“…The reason could be that excessive impact load breaks down the coal matrix inside the coal body, causing small molecule compounds in the coal matrix to block the large pores, thereby reducing porosity 20,21 . There are a large number of pores and cracks in the coal body, 22 and there are pore throats and throats of different sizes 23,24 . When the coal matrix is broken by the impact load, it will cause small molecule compounds to block the throats at the connection between the medium and large pores, thus making the large pores become micropores and reducing the plane porosity of the coal body. Energy embodied by excessive impact loads tends to damage rather than smooth the pores.…”

Section: Discussionmentioning

confidence: 99%

Pore morphology changes and quantitative analysis and evaluation of high‐rank coal samples after impact

Wang,

Han,

Yue

2024

Energy Science & Engineering

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The influencing mechanism of impact loads on the pore morphology of high‐rank coal has been extensively investigated since mining safety is greatly determined by the ensuing state of gas occurrence. In this work, we propose a combined use of a scanning electron microscope and Image Pro Plus software to examine the impact‐induced changes in pore characteristics. Impact loads of 0, 28.46, 51.8, and 58.7 MPa were applied to the coal samples in various directions (parallel/vertical/45° oblique). The results show that the pore connectivity of coal samples is enhanced following the impact load, and the number and diameter of pores are significantly increased on the whole. Surface porosity and roundness of the coal body first rise and then fall as the impact load increases. Following the impact load, surface porosity and roundness of the coal body significantly increase in the vertical and oblique bedding directions, while decreasing in the horizontal bedding direction.

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“…For different-rank coals, pores and cracks are distributed in different ways and the contents of organic matters and minerals also differ notably, which directly determines and affects the mechanical properties [33,34]. In order to explore the influence of coal rank on the natural frequency of coal, frequency domain diagrams for Face A of the 100 mm ×100 mm ×100 mm typical dried coal samples of high, middle, and low rank were obtained according to Scheme (4) in Section 3.3 (Figure 9).…”

Section: Influence Of Coal Rankmentioning

confidence: 99%

Natural Frequency of Coal: Mathematical Model, Test, and Analysis on Influencing Factors

et al. 2022

Self Cite

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The difficulty in enhancing the low permeability of deep coal seams is the key problem restricting gas extraction. The technology of coal rock resonance and permeability enhancement excited by vibration wave is hailed as a new technology to enhance coal seam permeability. In particular, the effect of resonance and permeability enhancement is remarkable when the excitation frequency is exactly the same as the natural frequency of coal. In order to promote the application of the technology, the first step is to explore the variation characteristics of coal natural frequency and its influencing factors. In this study, two mathematical models of coal natural frequency were established, and the variations and influencing factors of coal natural frequency were discussed through an experiment on the natural frequency of coal. The results show that coal vibration has multiorder natural frequency which grows with the increase of the order. In addition, the natural frequency of coal is closely related to its elastic modulus, density, size, mass, stiffness, and other physical and mechanical parameters. The larger the coal size and mass are, the lower the natural frequency would be. The natural frequency parallel to the bedding plane is higher than that perpendicular to the bedding plane. For the saturated coal sample, moisture changes its density and reduces its elastic modulus. Consequently, its natural frequency is lower than that of the dried coal sample. The difference of organic matter and mineral content coal of different rank affects the physical and mechanical properties of coal, which leads to the difference in natural frequency of different-rank coals. The natural frequencies of different-rank coal show bituminous > anthracite > lignite. The natural frequencies of coal samples under different influencing factors are all tens of Hz. Thus, the vibration excitation of coal under the low-frequency condition is the focus of future research. The study can provide a theoretical basis for the technology of coal resonance and permeability enhancement excited by vibration wave.

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Pore Structure Characteristics and Evolution Law of Different-Rank Coal Samples

Cited by 8 publications

References 18 publications

Study on Multifractal of Coal Pore Structure Based on Low Pressure Argon Adsorption and Its Effect on Gas Adsorption/Desorption

Study on Multifractal of Coal Pore Structure Based on Low Pressure Argon Adsorption and Its Effect on Gas Adsorption/Desorption

Pore morphology changes and quantitative analysis and evaluation of high‐rank coal samples after impact

Natural Frequency of Coal: Mathematical Model, Test, and Analysis on Influencing Factors

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