Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The injection of CO2 into oil reservoirs (CO2 enhanced oil recovery, CO2-EOR) can result in higher production, and the use of CO2 as a mining resource can thus be an economic driver for oil production. The thermodynamic properties of CO2 mixtures are essential for the design and operation of CO2-EOR systems. This paper addresses the (p, ?, T) properties of a CO2 + tetradecane solution. Experimental densities were measured on a magnetic suspension balance, and experiments were performed at pressures from 10 MPa to 19 MPa, temperatures from 313.15 K to 353.15 K, and CO2 mole fractions of x1 = 0, 0.2469, 0.5241, 0.7534, and 0.8773. Solution densities increased with pressure and decreased with temperature over the experimental range. Density versus the CO2 mole fraction increased at first and then decreased at higher temperatures and higher CO2 concentrations. The compositions intersect when plotted, and the pressure intersection increased with temperature. The excess molar volumes of the binary mixtures were negative over the entire range of composition, which increased with increasing pressure and became more negative with increasing temperature. The PC-SAFT and tPC-PSAFT equations of state were used to calculate the densities of the binary mixtures. New PC-SAFT parameters for tetradecane were obtained by fitting to experimental densities directly. In both PC-SAFT and tPC-PSAFT, the binary interaction parameter kij was fitted as a function of the CO2 mole fraction. The tPC-PSAFT combined with the correlation of kij gave the best predictions of the CO2 + tetradecane mixture densities.