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Hu T, Shi B, Yue J, Liang Y, Wang C, Han Q. Experimental Study on Coal and Gas Outburst Risk under Different Water Content Rates in Strong Outburst Coal Seams. ACS OMEGA 2024; 9:1485-1496. [PMID: 38222594 PMCID: PMC10785284 DOI: 10.1021/acsomega.3c07896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 01/16/2024]
Abstract
To investigate the alleviation potency of coal seam water infusion on coal and gas outburst, this paper focuses on the Qidong coal mine outburst coal seam, where outburst accidents have occurred many times, and obtains the impact of water content on outburst prediction parameters by studying the features of outburst parameters and gas desorption law under different water content rates. How water content affects outburst was also researched through the use of a self-made outburst simulation test system, and the relationship between water content and outburst intensity and critical gas pressure was studied. It can be concluded that with the rise of water content, the initial velocity of gas diffusion, the gas desorption index of drilling cuttings, and the adsorption constant a decrease, but the firmness coefficient (f) increase, and these indicators are exponentially related to the water content. Meanwhile, as the water content raises, the outburst pressure threshold increases, the outburst intensity gradually decreases, and the less likely outburst occurs. Under 0.5 MPa pressure, as the water content arose from 2.02 to 5.14%, the outburst intensity was significantly weakened, while no outburst occurred as the water content reached to 10.25%. Fitting analysis of the influence curve of outburst parameters and comparing the vital values of outburst prediction indexes finally determined that the water content rate of 5.14% could be used as a key index for water injection measures for coal and gas outburst prevention coal seam in Qidong coal mine no. 9. This research offers a guiding significance for the outburst prevention measures of water infusion in outburst coal seams and gives a feasible scheme for the safe mining of outburst coal mines.
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Affiliation(s)
- Tao Hu
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Biming Shi
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
- Key
Laboratory of Safety and High-efficiency Coal Mining, Ministry of
Education, Anhui University of Science and
Technology, Huainan, Anhui 232001, China
| | - Jiwei Yue
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Yuehui Liang
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Cheng Wang
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Qijun Han
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
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Chen M, Chen X, Zhang X, Tian F, Sun W, Yang Y, Zhang T. Experimental Study of the Pore Structure and Gas Desorption Characteristics of a Low-Rank Coal: Impact of Moisture. ACS OMEGA 2022; 7:37293-37303. [PMID: 36312393 PMCID: PMC9608427 DOI: 10.1021/acsomega.2c03805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Coal-water interactions have a prominent impact on the prediction of coal mine gas disasters and coalbed methane extraction. The change of characteristics in the microscopic pores of coal caused by the existence of water is an important factor affecting the diffusion and migration of gas in coal. The low-pressure nitrogen adsorption experiments and gas desorption experiments of a low-rank coal with different equilibrium moisture contents were conducted. The results show that both the specific surface area and pore volume decrease significantly as the moisture content increases, and the micropores (pore diameter <10 nm) are most affected by the water adsorbed by coal. In particular, for a water-equilibrated coal sample at 98% relative humidity, micropores with pore sizes smaller than 4 nm as determined by the density functional theory model almost disappear, probably due to the blocking effects of water clusters and capillary water. In this case, micropores with a diameter less than 10 nm still contribute most of the specific surface area for gas adsorption in coal. Furthermore, the fractal dimensions at relative pressures of 0-0.5 (D 1) and 0.5-1 (D 2) calculated by the Frenkel-Halsey-Hill model indicate that when the moisture content is less than 4.74%, D 1 decreases rapidly, whereas D 2 shows a slight reduction as the moisture content increased. In contrast, when the moisture content exceeds 4.74%, further increases in the moisture content cause D 2 to decrease significantly, while there is nearly no change for D 1. The correlation analyses show that the ultimate desorption volume and initial desorption rate are closely related to the fractal dimension D 1, while the desorption constant (K t) mainly depends on the fractal dimension D 2. Therefore, the gas desorption performances of coal have a close association with the pore properties of coal under water-containing conditions, which indicate that the fluctuation in moisture content should be carefully considered in the evaluation of gas diffusion and migration performances of in situ coal seams.
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Affiliation(s)
- Mingyi Chen
- School
of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang050043, China
- Hebei
Province Technical Innovation Center of Safe and Effective Mining
of Metal Mines, Shijiazhuang Tiedao University, Shijiazhuang050043, China
- Key
Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Ministry of Education, Shijiazhuang050043, China
| | - Xiaoyun Chen
- School
of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang050043, China
| | - Xuejie Zhang
- School
of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang050043, China
- Key
Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Ministry of Education, Shijiazhuang050043, China
| | - Fuchao Tian
- State
Key Laboratory of Coal Mine Safety Technology, China Coal Technology
& Engineering Group, Shenyang Research
Institute, Shenfu Demonstration
Zone113122, China
| | - Weili Sun
- State
Key Laboratory of Coal Mine Safety Technology, China Coal Technology
& Engineering Group, Shenyang Research
Institute, Shenfu Demonstration
Zone113122, China
| | - Yumeng Yang
- School
of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang050043, China
- Hebei
Province Technical Innovation Center of Safe and Effective Mining
of Metal Mines, Shijiazhuang Tiedao University, Shijiazhuang050043, China
- Key
Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Ministry of Education, Shijiazhuang050043, China
| | - Tonghao Zhang
- School
of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang050043, China
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Zhou A, Wang K, Fan L, Tao B. Propagation characteristics of pulverized coal and gas two-phase flow during an outburst. PLoS One 2017; 12:e0180672. [PMID: 28727738 PMCID: PMC5519042 DOI: 10.1371/journal.pone.0180672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 06/19/2017] [Indexed: 11/25/2022] Open
Abstract
Coal and gas outbursts are dynamic failures that can involve the ejection of thousands tons of pulverized coal, as well as considerable volumes of gas, into a limited working space within a short period. The two-phase flow of gas and pulverized coal that occurs during an outburst can lead to fatalities and destroy underground equipment. This article examines the interaction mechanism between pulverized coal and gas flow. Based on the role of gas expansion energy in the development stage of outbursts, a numerical simulation method is proposed for investigating the propagation characteristics of the two-phase flow. This simulation method was verified by a shock tube experiment involving pulverized coal and gas flow. The experimental and simulated results both demonstrate that the instantaneous ejection of pulverized coal and gas flow can form outburst shock waves. These are attenuated along the propagation direction, and the volume fraction of pulverized coal in the two-phase flow has significant influence on attenuation of the outburst shock wave. As a whole, pulverized coal flow has a negative impact on gas flow, which makes a great loss of large amounts of initial energy, blocking the propagation of gas flow. According to comparison of numerical results for different roadway types, the attenuation effect of T-type roadways is best. In the propagation of shock wave, reflection and diffraction of shock wave interact through the complex roadway types.
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Affiliation(s)
- Aitao Zhou
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, China
- School of Resource & Safety Engineering, China University of Mining & Technology (Beijing), Beijing, China
| | - Kai Wang
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, China
- School of Resource & Safety Engineering, China University of Mining & Technology (Beijing), Beijing, China
- * E-mail:
| | - Lingpeng Fan
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, China
- School of Resource & Safety Engineering, China University of Mining & Technology (Beijing), Beijing, China
| | - Bo Tao
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, China
- School of Resource & Safety Engineering, China University of Mining & Technology (Beijing), Beijing, China
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