Phase Equilibrium Study of Ethane + Perfluorohexane System across Temperatures from 292.89 to 317.92 K and Pressures from 0.513 to 4.913 MPa

This study provides comprehensive experimental vapor-liquid equilibrium data for a system composed of perfluorohexane and ethane at four temperatures (292.89 to 317.92) K and pressures spanning from 0.513 to 4.913 MPa. The experimental investigation was achieved using a “static-analytic” equipment fitted with a capillary sampler for the equilibrium phases. The expanded uncertainties in the measurement of temperatures, pressures, and mole fractions were determined to be within 0.04 K, 0.003 MPa, and less than 0.03, respectively. The phase equilibrium data were successfully modeled via the phi-phi approach using two sets of thermodynamic models, i.e., the Peng-Robinson equation of state with the Wong-Sandler mixing rule or the Soave-Redlich-Kwong equation of state with the predictive Soave-Redlich-Kwong mixing rule. The parameters of both models were adjusted using the ordinary least-squares objective function. The PR-MC-WS-NRTL model slightly outperforms the SRK-MC-PSRK-NRTL model in representing experimental data, with both models showing minor differences and bias P, bias y, and AAD y values within 1%, while AAD P values exceed 1% but remain nearly identical for both. A comparison of the VLE data for the C₂H₆ + C₆F₁₄ and the CO₂ + C₆F₁₄ systems reveals that C₆F₁₄ exhibits strong selectivity for C₂H₆ over that of CO₂ at high pressures.