Experimental VLE Data and Thermodynamic Modeling of the Ethane + Hexafluoropropylene Oxide (HFPO) System

This study presents experimental vapor–liquid equilibrium (VLE) data for two fluorinated-based systems. Experimental VLE data for the R116 + propane system at 292.22 and 296.93 K were initially undertaken to validate the experimental setup and procedure. Subsequently, VLE data for the ethane + HFPO system were measured at five isotherms (283.39, 290.32, 298.67, 308.42, and 318.45 K), encompassing three below and two above the critical temperature of ethane, the more volatile component. The measurements were conducted using a static-analytical setup, with equilibrium-phase sampling performed via a capillary sampler and composition analysis carried out using gas chromatography. The uncertainties in the measurements were estimated to be within 0.07 K for temperature, 11 kPa for pressure, and 0.009 and 0.008 mole fractions for the liquid- and vapor-phase compositions, respectively. Thermodynamic modeling of VLE data for the two systems was undertaken using the homogeneous “Φ–Φ” approach, employing the Peng–Robinson equation of state with the Mathias–Copeman alpha function. A combination of the Wong–Sandler mixing rule with the nonrandom two-liquid activity coefficient model was utilized to account for fluid mixture behavior. This modeling approach yielded satisfactory results, as shown by AAD_xy and bias_xy values of less than 3%.