Investigation of pore structure characteristics and adsorption characteristics of coals with different destruction types

Yue, Jiwei; Wang, Zhaofeng; Chen, Jinsheng; Zheng, Menghao; Wang, Qiao; Lou, Xiufang

doi:10.1177/0263617419868076

Cited by 39 publications

(34 citation statements)

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“…In particular, the adsorption capacity of coalbed methane (CBM) is closely related to the pore development degree and pore structure characteristics. Therefore, the research on the pore structure characteristics of coal is meaningful for gas disaster prevention and CBM extraction and utilization [8][9][10]. As specified by the Hodot decimal classification standard [11][12][13], the pores in coal can be divided into five categories according to the pore size, i.e., micropores (<10 nm), small pores (10-100 nm), mesopores (100-1,000 nm), macropores (>10,000 nm), and visible pores (>100,000 nm).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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In this study, the full-size pore structure characteristics of six different-rank coal samples were investigated and analyzed from three perspectives, namely, pore shape, pore volume, and pore specific surface area, by performing a high-pressure mercury injection experiment and a low-temperature nitrogen adsorption experiment. Next, the full-size pore volumes and pore specific surface areas of the six coal samples were accurately characterized through a combination of the two experiments. Furthermore, the relationships between volatile matter content and pore volume and between volatile matter content and pore specific surface area were fitted and analyzed. Finally, the influences of metamorphic degree on pore structure were discussed. The following conclusions were obtained. The pore shapes of different-rank coal samples differ significantly. With the increase of metamorphic degree, the full-size pore volume and pore specific surface area both decrease first and then increase. Among the pores with various sizes, micropores are the largest contributor to the full-size pore volume and pore specific surface area. The fitting curves between volatile matter content and pore volume and between volatile matter content and pore specific surface area can well reflect the influence and control of metamorphic degree on pore volume and pore specific surface area, respectively. With the increase of volatile matter content, the pore volume and the pore specific surface area both vary in a trend resembling a reverse parabola.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…Coal and gas outburst is a complex dynamic phenomenon associated with coal, rock, and gas in coal mines, which is one of the most serious natural disasters in the process of coal mining (Li et al, 2017;C. Wang et al, 2017;Yue et al, 2019aYue et al, , 2019b. Coalbed methane is considered a driving force of coal and gas outbursts.…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Pore Structure and Fractal Characteristics of Soft and Hard Coals With Same Coalification

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et al. 2021

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Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical significance for coal bed methane and the prevention of dynamic disasters such as coal and gas outbursts. This study investigates the pore structure and fractural characteristics of soft and hard coals using nitrogen and carbon dioxide (N2/CO2) adsorption. Coal samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size (0.2-0.25mm). N2/CO2 adsorption tests were performed to evaluate the pore size distribution (PSD), specific surface area (SSA), and pore volume (PV). The pore structure was characterized based on fractural theory. The results unveiled that the strength of coal has a significant influence on pore structure and fracture dimensions. The obvious N2-adsorption isotherms of the coals were verified as Type IV (A) and Type II. The shape of the hysteresis loops indicates the presence of slit-shaped pores. There are significant differences in SSA and PV between both coals. The soft coal showed larger SSA and PV than hard coal that shows consistency with adsorption capacity. The fractal dimensions of soft coal are respectively larger than that of hard coal. The greater the value of D1 (complexity of pore surface) of soft coal is, the larger the pore surface roughness and gas adsorption capacity is. The results enable us to conclude that the characterization of pores and fractures of soft and hard coals is different, tending to different adsorption/desorption characteristics and outburst sensitivity. In this regard, results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.

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“…[18][19][20] Field tests have shown that the gas emission from coal increases during the water injection process 18,[21][22][23] ; in contrast, experimental results have shown that an increase in the moisture content of coal has a significant inhibitory desorption effect on the adsorbed gas. 24,25 Thus, it is necessary to determine the influence of external water on the desorption character of the adsorbed coalbed methane in coal.…”

Section: Introductionmentioning

confidence: 99%

“…As the permeability is often very low for complex coal structures, hydraulic methods that enable an increase in the water content and thus reduce the gas pressure of coal seams, including coal seam water injection, 17 hydraulic punching, and hydraulic extrusion, are the main techniques used to improve permeability before coal mining 18‐20 . Field tests have shown that the gas emission from coal increases during the water injection process 18,21‐23 ; in contrast, experimental results have shown that an increase in the moisture content of coal has a significant inhibitory desorption effect on the adsorbed gas 24,25 . Thus, it is necessary to determine the influence of external water on the desorption character of the adsorbed coalbed methane in coal.…”

Section: Introductionmentioning

confidence: 99%