A Study of the Differences in the Gas Diffusion and Migration Characteristics of Soft and Hard Coal in High Gas Coal Seams

Yuan, Anying

doi:10.1155/2020/8825625

Cited by 4 publications

(4 citation statements)

References 25 publications

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“…A large number of cases have proven that mining the protective coal seam is an effective measure to reduce the gas pressure in the protective coal seam and improve the permeability of the coal seam 33 – 35 . After the protective layer is mined, the gas pressure in the coal seam obviously changes.…”

Section: Resultsmentioning

confidence: 99%

“…After the protective layer is mined, the gas pressure in the coal seam obviously changes. According to the research results of Yuanliang, an academician at the Chinese Academy of Engineering 35 , the gas pressure in the protected layer obviously changed before and after mining of the protective layer, and the measured minimum gas pressure was 0.2 MPa (Fig. 7 ).…”

Section: Resultsmentioning

confidence: 99%

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Study of the solid–gas–stress coupling model and its application

Shi

Song

2023

Sci Rep

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Coal mines may change from non-outburst mines into coal and gas outburst mines with increasing mining depth. Therefore, scientific and rapid prediction of the coal seam outburst risk and effective prevention and control measures could ensure coal mine safety and production. This study aimed to propose a solid–gas–stress coupling model and assessed its applicability in predicting the coal seam outburst risk. Based on a large amount of outburst case data and the research results of previous scholars, coal and coal seam gas constitute the material basis of outbursts, and gas pressure is the energy source of coal seam outbursts. A solid–gas–stress coupling model was proposed, and a solid–gas–stress coupling equation was established via regression. Among the three major outburst factors, the sensitivity to the gas content during outbursts was the lowest. The causes of coal seam outbursts with a low gas content and the effect of the structure on outbursts were explained. It was theoretically revealed that the coupling of the coal firmness coefficient, gas content and gas pressure determined whether coal seams could experience outbursts. This paper provided a basis for assessing coal seam outbursts and classifying outburst mine types and listed application examples of solid–gas–stress theory.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Study of the solid–gas–stress coupling model and its application

Shi

Song

2023

Sci Rep

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“…The surface area of soft coal is 1.6 times that of hard coal. At the same time, the gas adsorption capacity of soft and hard coal is also different. − Yuan studied in detail the characteristics of gas diffusion and migration between soft and hard coal from three research perspectives of macrostructure, mesostructure, and microstructure and explored the root cause of the difference in gas diffusion and migration. For the macroscopic structure, the particles of soft coal are flaky and nail shaped.…”

Section: Introductionmentioning

confidence: 99%

Study on the Critical Value of Residual Gas Content Based on the Difference of Adsorption Structure between Soft and Hard Coal

Liang

Lin

et al. 2021

ACS Omega

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In view of the difference of the adsorption structure between soft and hard coal, there is a big difference in the critical value of the inspection index for the regional outburst risk caused by the gas content. For the coal seams with soft and hard coal stratification, the model of gas content in the equilibrium state was established first, and the microscopic parameters of different rank coals were determined by the low-temperature liquid nitrogen adsorption test and mercury intrusion test. Then, the adsorption capacity of coal samples was determined by the adsorption test. Finally, the residual gas content of the coal seam in the equilibrium state was calculated based on the adsorbed gas content, and the critical value of prediction indexes of regional outburst based on the residual gas content was studied. The results show that for the same metamorphic degree, the specific surface area of soft coal is larger than that of hard coal. However, under the same gas pressure, the residual gas content of hard coal of anthracite and lean coal is greater than that of soft coal with the same metamorphic degree, while that of meager-lean coal and gas-fat coal is opposite. It is suggested to adopt the small value (rounded) of the measured gas content of soft and hard coal at 0.74 MPa as the critical value of the residual gas content in the regional effect test from the economic perspective. It is of great significance to determine the critical standard of the residual gas content in the regional effect test according to local conditions for reducing the cost of outburst prevention work.

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“…Also, it has been indicated that the inflection point of the low-temperature liquid nitrogen adsorption will be advanced following tectonic activities, with the coal tending to have smaller average pore sizes and higher adsorption pore volumes and pore-specific surface areas. Moreover, the adsorption capacity of the coal following increased tectonic activities has been found to be significantly higher than that of indigenous coal of the same coal grade [29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

A Multiscale Structural Analysis of Soft and Hard Coal Deposits in Deep High‐Gas Coal Seams

Yuan

Hou

2021

Advances in Civil Engineering

Self Cite

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In recent years, with the increases in coal mining depths, the risk of coal seam outburst occurrences has increased. Therefore, it is of major significance to study the multiscale structures of soft and hard coal deposits in order to prevent and control the coal and gas outbursts. In this research investigation, soft and hard coal multiscale structures were comprehensively examined using various laboratory methods. The results revealed the following: (1) From a macrostructural aspect, the physical and mechanical properties of the soft coal were weaker than those of the hard coal. It was found that the majority of the examined specimens were characterized by scaly structures without blocks larger than 50 mm. The hard coal was observed to be mainly massive with only a small part being clastic. Therefore, the structural characteristics were considered to be stable. (2) From a microstructural perspective, the surfaces of the soft coal specimens were observed to be rough. The pores were found to be more developed, with the edge of pores being mainly hackly. At the same time, fractures were also relatively developed, showing good connectivity. (3) From a micropore structural perspective, it was found that the BET-specific surface areas and BJH-specific surface areas of the soft coal specimens were higher than those of the hard coal specimens, which indicated that the gas adsorption and diffusion migration abilities of the soft coal were greater than those of the hard coal. (4) It was suggested from the study results that the ventilation and gas extraction processes should be strengthened in the mining activities of coal seams with high, soft stratification content. At the same time, the methods used for water injection modification should be enhanced in order to improve the mechanical stability of soft coal. Consequently, the instantaneous released gases will be decelerated, and the occurrences of coal and gas outburst events in mine working faces can be prevented.

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A Study of the Differences in the Gas Diffusion and Migration Characteristics of Soft and Hard Coal in High Gas Coal Seams

Cited by 4 publications

References 25 publications

Study of the solid–gas–stress coupling model and its application

Study of the solid–gas–stress coupling model and its application

Study on the Critical Value of Residual Gas Content Based on the Difference of Adsorption Structure between Soft and Hard Coal

A Multiscale Structural Analysis of Soft and Hard Coal Deposits in Deep High‐Gas Coal Seams

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