Equation of state for methane in nanoporous material at supercritical temperature over a wide range of pressure

Abstract

The methane storage behavior in nanoporous material is significantly different from bulk phase, and has a fundamental role in methane extraction from shale and its storage for vehicular applications. Here we show that the behavior and mechanisms of the methane storage are mainly dominated by the ratio of the interaction between methane molecules and nanopores wall to the methane intermolecular interaction, and the geometric constraint. By linking the macroscopic properties of methane storage to the microscopic properties of methane molecules-nanopores wall molecules system, we develop an equation of state for methane at supercritical temperature over a wide range of pressure. Molecular dynamic simulation data demonstrate that this equation is able to relate very well the methane storage behavior with each of key physical parameters, including pore size, shape, wall chemistry and roughness. Moreover, this equation only requires one fitted parameter, and is simply and powerful in application.

Phase Behavior of Hydrocarbon Fluids in Shale Reservoirs, Considering Pore Geometries, Adsorption, and Water Film

“…Pores with a radius of less than 10 nm account for up to 42% of the total pore volume. , In nanopores, the thermodynamic properties and phase behavior of confined fluids are very different from those of bulk fluids due to the confinement effect . The fluid thermodynamic properties induced by the confinement effect include the critical properties, density, viscosity, surface tension, and compressibility factor of the fluid. , …”

“… 12 The fluid thermodynamic properties induced by the confinement effect include the critical properties, density, viscosity, surface tension, and compressibility factor of the fluid. 40 , 41 …”