New Vapor–Liquid Phase Equilibrium Data of CO2 in Several Heavy n-Alkanes at High Pressures

New phase equilibrium data of CO2 in n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane were measured at temperatures from 333.15 to 373.15 K up to 23.73 MPa by a constant-volume method. Thermodynamic properties of Gibbs free energy (ΔsolG), enthalpy change (ΔsolH), entropy change (ΔsolS), and Henry’s coefficient (H) were calculated and analyzed for elucidating the dissolution mechanism of CO2 in alkanes. Results showed that the CO2 solubility increased with increasing pressure but decreased with increasing temperature and carbon number. In addition, increasing carbon number also led to an increase in the minimum miscibility pressure (MMP) of alkanes with CO2 and thus limited CO2 solubility in alkanes.