Interfacial tension of (methane plus nitrogen) plus water and (carbon dioxide plus nitrogen) plus water systems

Interfacial tension data of (CH4 + N-2) + H2O and (CO2 + N-2) + H2O systems were measured using a pendant-drop method. The temperature and pressure ra nges were 298-373 K and 1-30 MPa, respectively. The effects of gas composit ion, temperature, and pressure on the interfacial tension of the systems st udied have been investigated. The linear gradient theory (LGT) was used to calculate the interfacial tensions of these two systems. The results show g ood agreement between the calculated and experimental interfacial tension d ata for the (CH4 + N-2) + H2O system. However, it was found that the LGT mo del with one adjustable parameter is inadequate to give accurate prediction s for the CO2 + H2O system and thus is not suitable for the description of the (CO2 + N-2) + H2O system.