Molecular dynamics analysis of influencing factors of CH4diffusion in coal

被引：0
|
作者：
Tang J. [1 ]
Qiu Y. [1 ]
Ma Y. [1 ]
机构：
[1] School of Mechanics and Engineering, Liaoning Technical University, Fuxin
来源：
Meitan Kexue Jishu/Coal Science and Technology (Peking) | 2021年 / 49卷 / 02期
关键词：
Adsorption; Coal; Diffusion coefficient; Methane; Molecular dynamics;
D O I：
10.13199/j.cnki.cst.2021.02.011
中图分类号：
学科分类号：
摘要：
In order to analyze the iniluenee faetors of methane diffusion in coal from the microscopic point of view, taking three kinds of coal samples from Sunjiawan, Datong and Shuangyashan mining areas as the research objects, based on the XRD results, three kinds of coal macromolecular structure models were constructed. The effects oi pressure, temperature, CO2and H2O on the diffusion of CH4molecules in coal were studied by molecular dynamics simulation. The change law oi CH4diiiusion coefficient in coal under different influence faetors is given. The results show that with the increase of pressure, the diffusion coefficient of CH4molecules in the three coals decreases first and then tends to be stable. When the pressure increases to a certain value, the diffusion coefficient of CH4molecules in the three coals from Sunjiawan, Datong and Shuangyashan will be stable at 1. 084x10-8, 0. 770x10-8and 1. 137x10-8m2/s, respectively. Under the same pressure condition, the order of CH4molecular diffusion rate from large to small is Shuangyashan coal, Sunjiawan coal, Datong coal. With the increase of temperature, the mean orientation shift of CH4in the three kinds of coal increases, which is conducive to the diffusion of CH4molecules, but not conducive to its adsorption. The effect of temperature change on the diffusion rate of CH4molecules in three kinds of coal is from the largest to the least as Sunjiawan coal, Shuangyashan coal, Datong coal. Within a certain range, the increase of H20 content has a hindrance to the diffusion of CH4molecules. The increase of H2O content has a greater effect on the diffusion rate of CH4molecules in Sunjiawan and Datong coals, but a smaller effect on the diffusion rate of CH4molecules in Shuangyashan coals. H2O gas injection method is more effective in Sunjiawan and Datong coals. The molecular diffusion coefficient of CH4decreases with the increase of CO2content. The inhibition effect of CO2on the diffusion of CH4molecules in coal is stronger to weaker than that in mining areas, Suangyashan coal. Compared with H2O, CO2has a stronger inhibition effect on the diffusion of CH4molecules in coal seam. From the perspective of molecular dynamics diffusion coefficient, the coal seam CO2injection gas recovery method is more effective. © 2021 Meitan Kexun Jishu/Coal Science and Technology (Peking). All rights reserved.
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页码：85 / 92
页数：7
相关论文
共 23 条
  • [1] CHEN Jun, DAI Gang, Wei HL, Et al., Analysis of CO<sub>2</sub>injecti on technology to improve CBM recovery [J], Chinese and Foreign Energy, 21, 3, pp. 38-42, (2016)
  • [2] CARLSON G A., Computer simulation of the molecular structure of bituminous coal, Energy and Fuels, 6, pp. 771-778, (1992)
  • [3] LI Xiaofeng, WU Zhiyong, HE Wenjun, Et al., Prediction of thermodynamic properties of fluids by molecular simulation[J], Journal of Computer and Applied Chemistry, 28, 8, pp. 979-981, (2011)
  • [4] LIM S Y, TSOTSIS T T., Molecular simulation of diffusion and sorption of gases in an amorphous polymer[J], Journal of Chemical physics, 119, 1, pp. 496-503, (2003)
  • [5] MACEDONIA M D, MOORE DD, MAGINN E J, Et al., Adsorption studies of methane, ethane, and arg on in the Zeolite Mordenite
  • [6] Molecular Simulations and experiments [J], Langmuir, 16, 8, pp. 3823-3534, (2000)
  • [7] HABGOOD H W., The kinetics of molecular sieve action. sorption of nitrogen-methane mixtures by linder molecular sieve 4A[J], Canadian Journal of Chemisty, 36, 10, pp. 1384-1397, (2011)
  • [8] VANT N, DO DD, NICHOLSON D., A new molecular model for water adsorption ongraphitized carbon Black [J], Carbon, 6, 6, pp. 629-636, (2014)
  • [9] ZHANG Q, LI C W, WU Q, Et al., Effect of dry water on methane separation and recovery from coal mine gas based on hydrate [J], RSC Advances, 28, 8, pp. 27171-27180, (2018)
  • [10] KIKAN B S, SOW JANYA K, ESWARICII VV, Et al., Illustration of hydratebased methane gas separation in coal bed methane type gas composition at lower pressures [J], Current Science, 114, 3, pp. 661-666, (2018)
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