Study on Methane Adsorption in Graphite Slit-pores by Molecular Dynamics Simulation
Adsorption, desorption and flow of shale gas are important processes in shale gas exploration. The main component of shale gas is methane. So the adsorption of methane in slit was studied by molecular dynamics simulation. In this paper, it has been studied that temperature, pressure, slit width, slit material and water in slits effect on methane adsorption. The methane density difference between bulk phase and interface increases at first, and it will decrease with increasing temperature or pressure. When the slit width is large, it only has a significant influence on the free region size; oppositely, the smaller slit width will decrease the size of adsorption region and the number of adsorption layers. The slit is made of different materials which has significantly different methane adsorption capacity. The methane adsorption capacity is graphite > kaolinite > quartz. Existence of water in slits will reduce methane content. When the moisture
content increased up to a certain extent, the surface of slit will be completely covered by water films and the adsorption methane will almost disappear.