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Liang Y, Shi B, Yue J, Zhang C, Shen X, Hu T, Han Q. Desorption Characteristics of CH 4-C 2H 6 Mixed Gas in Heavy Hydrocarbon-Rich Coal Seams. ACS OMEGA 2024; 9:16176-16186. [PMID: 38617656 PMCID: PMC11007830 DOI: 10.1021/acsomega.3c10156] [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: 12/19/2023] [Revised: 03/07/2024] [Accepted: 03/13/2024] [Indexed: 04/16/2024]
Abstract
The gas desorption characteristics of coal are closely related to the gas content of the coal seam. The gas in heavy hydrocarbon-rich coal seams contains CH4 and C2H6 heavy hydrocarbons. However, most current research on the gas desorption characteristics of coal seams focuses on CH4 analysis, ignoring the influence of the C2H6 heavy hydrocarbon gas. To accurately determine the gas content of a heavy hydrocarbon-rich coal seam, methods based on CH4 analysis are inadequate and the desorption characteristics of CH4-C2H6 mixed gas must be clarified. This work experimentally and theoretically studies the desorption characteristics of single-component gas and CH4-C2H6 mixed gas from coal samples. The results show that increasing the adsorption-equilibrium pressure was found to increase the desorption quantity and desorption speed of single-component gas and increase the desorption quantity, desorption ratio, and diffusion coefficient of mixed gas. Under the same adsorption-equilibrium pressure, the desorption quantity and rate of single-component CH4 gas exceeded those of C2H6. The quantity and speed of mixed gas desorption increased with rising CH4 concentration and decreased with rising C2H6 concentration. The change in the mixed gas concentration during desorption reflects the distribution characteristics of light hydrocarbon components on the outer surface and heavy hydrocarbon components on the inner surface of coal. From the desorption characteristics of mixed gas, desorption models of mixed gas were obtained at different concentrations, laying a theoretical foundation for accurate determinations of gas contents in heavy hydrocarbon-rich coal seams.
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Affiliation(s)
- Yuehui Liang
- 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
| | - Jiwei Yue
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
- Technology
Research and Development Platform for Disaster Prevention and Control
Technology of Deep Coal Mining, Anhui University
of Science and Technology, Huainan 232001, China
- State
Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China
| | - Chengcheng Zhang
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Xiaojing Shen
- School
of Safety Science and Engineering, Anhui
University of Science and Technology, Huainan, Anhui 232001, China
| | - Tao Hu
- 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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Shen S, Wang H, Ren T, Wang Z, Cao T, Xin Z. Study on the Solution and Variation Law of Diffusion Coefficient Based on the Numerical Simulation Optimization Method. ACS OMEGA 2024; 9:3950-3961. [PMID: 38284093 PMCID: PMC10810006 DOI: 10.1021/acsomega.3c08335] [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: 10/23/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/30/2024]
Abstract
Since the diffusion coefficient is a key parameter to characterize the diffusion rate of methane molecules, its measurement and solution have always been a research hotspot. The diffusion coefficient is normally solved through analytical solutions of theoretical models, which is complex and poorly applicable. In comparison, the numerical simulation optimization method can seek a solution easily and quickly, providing a clue for solving such problem. In this paper, first, gas desorption experiments were conducted on coal samples with different initial gas equilibrium pressures, coal particle sizes, and metamorphic degrees. Combined with existing theoretical models, the numerical simulation optimization method was adopted to solve the diffusion coefficient of the coal particle. Furthermore, the applicability and advantages of the numerical simulation optimization method were discussed. Finally, the variation law of the diffusion coefficients was analyzed. The results demonstrate that the numerical simulation optimization method can not only solve the diffusion coefficient easily and quickly but also reveal the law of diffusion concentration with time. The d values between the solution results and the experimental data under different conditions are all smaller than 0.2, which proves the effectiveness and accuracy of the simulation optimization method. The diffusion coefficient of gas from coal particles is unrelated to the initial gas equilibrium pressure, yet it has a Z-shaped relationship with the coal particle size and a V-shaped relationship with the metamorphic degree.
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Affiliation(s)
- Shangkun Shen
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
| | - Haifeng Wang
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
| | - Tianwei Ren
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
| | - Zhiyuan Wang
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
| | - Tengyue Cao
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
| | - Zhengyang Xin
- Key
Laboratory of Coal Methane and Fire Control, Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
- National
Engineering Research Center for Coal and Gas Control, China University of Mining and Technology, Xuzhou 221116, China
- School
of Safety Engineering, China University
of Mining and Technology, Xuzhou 221116, China
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