Measurements and modeling of high-temperature, high-pressure density for binary mixtures of propane with n-decane and propane with n-eicosane

• High-temperature, high-pressure experimental binary mixture densities of propane with n-decane or n-eicosane are reported.
• Tait equation parameters to correlate experimental mixture densities are reported.
• EoS give better representation of (propane + decane) system than (propane + eicosane) system.
• Reports predictions with PC-SAFT, Peng–Robinson (PR), and volume-translated PR EoS.

Binary mixture density data are reported for propane (C3) with n-decane (C10) and with n-eicosane (C20) at T = (320 to 525) K and pressures to 265 MPa. The (C3 + C10) mixture density data are in good agreement with available literature data to 70 MPa, which is the maximum reported literature pressure. There are no available binary mixture density data to compare to the (C3 + C20) mixture density data reported in the present study. The mixture density data are correlated with the Tait equation to facilitate interpolation of the data at different experimental conditions. Equations of state that are suitable for reservoir simulations are used to model the reported data. These models include the Peng–Robinson equation of state (PREoS), a volume-translated PREoS fit to high temperature, high pressure (HTHP) pure component density data, the PC-SAFT EoS, and modifications of the PC-SAFT EoS developed for better representation of HTHP data. The models give superior density predictions for (C3 + C10) mixtures compared to (C3 + C20) mixtures.