Effect of internal moisture on CH4 adsorption and diffusion of coal: A molecular simulation study

Min, Hang; Wei, Chengmin; Qiao, Zhen

doi:10.1016/j.cplett.2021.139086

Cited by 17 publications

(15 citation statements)

References 42 publications

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“…Kang et al 6 investigated the influences of the temperature and pressure on methane diffusion in kaolinite. Hao et al 7 explored the effect of internal moisture on the adsorption property and diffusion behavior. However, the influence of slit pores on methane adsorption and diffusion is rarely considered, and its further elucidation is extremely important.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Diffusion of Methane in Coal Slit Pores: Insights into the Molecular Level

2022

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Coal contains multi-scale pore structures, which determine the adsorption and diffusion of methane. To further reveal the effect of the pore structure from the molecular level, we construct the different slit pore models of coal and carry out a series of molecular simulations. The results show that the increase of slit pores increases the absolute adsorption capacity and isosteric heat of adsorption. The increased slit pores can promote the selfdiffusion and transport diffusion of methane molecules. This research can provide a basis for the theory of the coal−methane interaction.

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Section: Introductionmentioning

confidence: 99%

Adsorption and Diffusion of Methane in Coal Slit Pores: Insights into the Molecular Level

2022

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“…The Forcite module mainly optimizes and calculates the energy of a periodic system and obtains the result file of energy optimization; it is a classical molecular mechanics tool that includes force field, charge distribution, and other parameter settings. 16 The Sorption module uses the Monte Carlo method to simulate the adsorption characteristics and adsorption isotherms of substances, and the model is modified on the basis of the molecular structure model of long-flame coal constructed by Lian. 17 The selected molecular substrate of long-flame coal is an amorphous molecular structure of an aromatic skeleton composed of 407 atoms, which mainly includes four elements: carbon, hydrogen, nitrogen, and oxygen.…”

Section: Methodsmentioning

confidence: 99%

“…The Forcite module and Sorption module in the software are used for optimization and molecular adsorption. The Forcite module mainly optimizes and calculates the energy of a periodic system and obtains the result file of energy optimization; it is a classical molecular mechanics tool that includes force field, charge distribution, and other parameter settings . The Sorption module uses the Monte Carlo method to simulate the adsorption characteristics and adsorption isotherms of substances, and the model is modified on the basis of the molecular structure model of long-flame coal constructed by Lian .…”

Section: Methodsmentioning

confidence: 99%

Effect of Moisture on Methane Adsorption Characteristics of Long-Flame Coal

et al. 2022

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Long-flame coal is a bituminous coal with the lowest metamorphic degree, accounting for 16.1% of China’s coal reserves. With increases in mining depths and intensities, mine gas disasters related to the mining of long-flame coal are becoming increasingly serious. Therefore, the exploration of the effect of moisture on the adsorption of methane in coal can provide support for popularizing the application of hydraulic measures in long-flame coal mining areas. In this paper, a molecular structure model of long-flame coal was established by molecular dynamics and the Monte Carlo method. The adsorption characteristics of methane in long-flame coal structures under different pressures were simulated, and the effects of different amounts of water on the methane adsorption and adsorption heat were explored. The results show that, under the same adsorption equilibrium pressure, the methane adsorption rate decreases with increasing water content, and with increasing adsorption equilibrium pressure, the adsorption capacity of methane increases gradually; this increasing trend is in agreement with the Langmuir equation. The water adsorption of coal is greater than the methane adsorption of coal. With the increase in the number of water molecules, when coal-based molecules adsorb methane and then adsorb water molecules, the adsorption heat of methane is reduced, and the desorption of methane molecules is promoted.

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“…10 Geofluids blockage leads to a large collection of high-pressure water in the borehole, and a large amount of water enters the pores and fissures of the coal body that inhibits the desorption of coal seam gas as well as blocks the gas seepage channels, reducing the efficiency of gas extraction in hydraulic perforated boreholes. Boreholes with smooth water drainage have little or no interference with the normal gas extraction of the borehole due to the low infiltration of high-pressure water into the coal seam [26]. Sampling and analysis of coal around the borehole with and without borehole blockage found that the water content of the coal around the plugged and unplugged boreholes was significantly higher than the water content of the coal around the unplugged boreholes with the highest water content in the coal around the boreholes where the drill pipe drop occurred.…”

Section: The Relationship Between Borehole Blockage and Impactmentioning

confidence: 99%

Research on Optimization of Large Flow Hydraulic Punching Process in Zhaozhuang Mine

Zhang

2022

Geofluids

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Taking hydraulic punching test of Zhaozhuang Mine as engineering background, by comparing the field application effects of different hydraulic punching processes, the relationship between coal moisture content around the borehole blockage and gas extraction effect was monitored and analyzed. The following conclusions were drawn: the occurrence of borehole blockage was the result of the comprehensive action of coal slag particle size and slag discharge capacity of punching return water. Blocking the borehole led to the accumulation of a large amount of punching high-pressure water and coal slag in the borehole, which compressed and infiltrated the surrounding coal body and reduced gas extraction efficiency of borehole. Under the condition of the same amount of coal produced by punching, the different punching methods led to the great difference in the influence radius of punching. The large flow three-stage coal-breaking hydraulic punching system developed according to the borehole blockage mechanism can effectively reduce the particle size of coal slag, increase the punching flow, effectively avoid borehole blockage, and improve gas extraction efficiency of borehole.

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Effect of internal moisture on CH4 adsorption and diffusion of coal: A molecular simulation study

Cited by 17 publications

References 42 publications

Adsorption and Diffusion of Methane in Coal Slit Pores: Insights into the Molecular Level

Adsorption and Diffusion of Methane in Coal Slit Pores: Insights into the Molecular Level

Effect of Moisture on Methane Adsorption Characteristics of Long-Flame Coal

Research on Optimization of Large Flow Hydraulic Punching Process in Zhaozhuang Mine

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