Determination of Compressed Liquid Densities for CO₂ + n-Decane Using a Vibrating Tube Densimeter

Understanding the density of CO₂ + n-decane is crucial for designing and operating CO₂ capture, transport, and storage. The safety and effectiveness of CO₂ burial is directly affected by the density of CO₂ + n-decane mixtures. The liquid densities of CO₂(1) + n-decane(2) mixtures with mole fractions of CO₂ x₁ = 0, 0.2032, 0.4434, 0.7589, and 0.8947 were measured using a vibrating tube densimeter. The combined expanded uncertainties of density with a level of confidence of 0.95 are estimated to be 0.6 kg·m⁻³. A total of 221 compressed liquid densities of CO₂(1) + n-decane(2) mixtures along the five isotherms between T = (283 and 363) K with pressures up to 100 MPa were presented. The densities of mixtures were correlated by the modified Tait equation, resulting in absolute average deviations between the experimental and calculated values of 0.028%, 0.013%, 0.017%, 0.044%, and 0.042%. In addition, the isothermal compressibility, isobaric thermal expansivity, and excess molar volume were derived from the modified Tait equation.