Interfacial properties of hydrogen-methane system from inhomogeneous fluid theories

An accurate description of the interfacial behavior in hydrogen-methane system is important for the hydrogen industry to design the transport and storage stages of hydrogen blends in the natural gas network. This research aims at providing accurate description of the interfacial behavior in this system up to 40 bar and temperatures from 95 up to 170 K, along with its macroscopic and microscopic properties calculated by the Density Gradient Theory (DGT) coupled with SAFT-VR- Mie equation of state. This modelling framework is compared with the Coarse-Grained Molecular Dynamics (CG-MD) simulations performed using the direct coexistence technique. It is demonstrated that both methods provide particularly accurate estimations of macroscopic and microscopic properties over a broad range of thermodynamic conditions, in which the surface tension computed with both DGT and MD simulations are in very good agreement with the available experimental data, confirming thus the reliability of the CG models.