( $${p, \rho , T, x}$$ ) Properties of $$\text{ CO}_{2}$$ /Propane Binary Mixtures at 280 K to 440 K and 3 MPa to 200 MPa

Abstract

The (p, $$\rho $$ , T, x) properties of binary mixtures of CO $$_{2}$$ (volume fraction purity 0.99999) and propane (mole fraction purity 0.9999) ( $$x_{1}$$ CO $$_{2}+x_{2}$$ propane; $$x_{1} = 0.1744$$ , 0.3863, 0.5837, and 0.7732) were measured in the compressed liquid phase using a metal-bellows variable volumometer. Measurements were conducted from 280 K to 440 K and 3 MPa to 200 MPa. The expanded uncertainties ( $$k = 2$$ ) were estimated to be temperature, $$<$$ 3 mK; pressure, 1.5 kPa ( $$p\le 7$$ MPa), 0.06 % (7 MPa $$< p\le 50$$ MPa), 0.1 % (50 MPa $$< p\le 150$$ MPa), 0.2 % ( $$p> 150$$ MPa); density, 0.10 %; and composition, $$4.4\times 10^{-4}$$ . At $$p >100$$ MPa and 280 K or 440 K, the uncertainties in density measurements increase to 0.14 % and 0.22 %, respectively. The data were compared with available equations of state. The excess molar volumes, $$v_\mathrm{m}^\mathrm{E}$$ , of the mixtures were calculated and plotted as a function of temperature and pressure.