Interfacial Tension Measurement and Calculation of (Carbon Dioxide + n‑Alkane) Binary Mixtures

Carbon dioxide (CO2) is often used as a process fluid in oil and gas reservoirs for enhancing the oil recovery. The interfacial tension of CO2 with hydrocarbons is an important thermophysical property for the design of such processes. The systematical measurements of equilibrium interfacial tensions for systems of (CO2 + single n-alkane) are currently scarce. In this work, the interfacial tensions of 11 (CO2 + n-alkane) binary systems were measured by the pendant drop method at temperatures of (323.15 and 353.15) K. The carbon number of n-alkane ranged from 10 to 20. The influences of temperature, pressure, and chain length of n-alkane on the interfacial tension were investigated. Additionally, the density gradient theory was applied to compute the surface tensions of these binary mixtures combined with the Patel–Teja equation of state plus volume translation approach. The calculation results are in good agreement with the experimental data.