Molecular dynamics simulations of interaction between sub-bituminous coal and water

Molecular simulation of CO2/CH4/H2O competitive adsorption and diffusion in brown coal

“…The interaction between sub-bituminous coal and water was examined by molecular dynamics simulations. 27 They claimed that the water molecules prefer to absorb with carboxylic groups. Although much work has been carried out, there are only a few studies focusing on the adsorption and diffusion of CO 2 /CH 4 mixture in brown coal, which account for around 47% of total coal reserve.…”

Methane Adsorption Influence and Diffusion Behavior of Coking Coal Macromolecules under Different Moisture Contents

“…36−39 It was found that the factors influencing the gas adsorption characteristics in the shale nanopores were mainly temperature, pressure, pore diameter, preadsorbed water, and location exchange of the adsorbent. 40 In the existing research, the working conditions for CH 4 adsorption were in the range of 280−460 K, 0.1−90 MPa, and 7−200 Å, and the preadsorbed water content was 0−0.8 g/cm 3 . 41 The working conditions for the study of CH 4 diffusion were in the range of 298−460 K, 0.1−90 MPa, and 8−100 Å, and the preadsorbed water content was 0.2−0.6 g/ cm 3 .…”

“…There are many factors affecting coal adsorption characteristics, among which water is one of the important factors. − Domestic and foreign experts and scholars have done a lot of research on the influence of coal moisture content on coal adsorption. − Under general conditions, with the increase of water content, the adsorption capacity of coal to gas decreases . For example, Gensterblum showed that with the increase of water content in coal seam and coal rank, the gas adsorption capacity decreased; Zhang found that water had a great influence on the adsorption capacity of low-rank coal, which reduced the methane adsorption capacity, but it had little effect on the adsorption capacity of high-rank coal.…”

“…These gas adsorption studies show the results of macro performance. In terms of numerical simulation, more than 140 different coal molecular structure models have been applied in relevant research, which largely reflected the coal structural characteristics. − Different coal molecular structures degraded and agglomerated under the interaction, which will affect the influence of the macro gas adsorption capacity. − It was found that the factors influencing the gas adsorption characteristics in the shale nanopores were mainly temperature, pressure, pore diameter, preadsorbed water, and location exchange of the adsorbent . In the existing research, the working conditions for CH 4 adsorption were in the range of 280–460 K, 0.1–90 MPa, and 7–200 Å, and the preadsorbed water content was 0–0.8 g/cm 3 .…”

Coalbed methane diffusion and water blocking effects investigated by mesoscale all-atom molecular dynamic simulations

“…Billemont et al studied the co-adsorption of CH 4 , H 2 O, and CO 2 in a porous coal structure that resembles coal, 29 while other researchers focused on CH 4 adsorption on moist kerogens. 30,31 The adsorption of liquid water on coal surfaces without methane has also been examined before, 32,33 and the effects of surfactants were discussed. 34 In this study, we aim to extend the understanding of the interaction between methane and water in a coal tube, specically, when the number of methane and water molecules is huge (>10 4 ) enough to form two separate phases rather than a single mixed phase.…”