Experimental and Theoretical Investigations of Solubility and Interfacial Tension for (R32 and R1234yf) with Polyol Ester (POE-68) Lubricant Mixtures

Owing to the urgent environmental concerns, numerous refrigerants containing R32 or R1234yf are widely regarded as a practical approach to replace the current refrigerants in air conditioning and refrigeration equipment. To promote the commercial application of these alternative refrigerants, experimental measurements of solubility and interfacial tension for R32/POE-68 and R1234yf/POE-68 mixtures were investigated by the isochoric saturation and pendant drop methods in the temperature range from 243.15 to 363.15 K and at pressures up to 5.78 MPa. Moreover, we have further discussed the comprehensive influence of temperature and pressure on thermophysical properties by both intermolecular interstices and intermolecular interactions. Under identical thermodynamic conditions, R1234yf has a superior solubility performance in the polyol ester (POE-68) lubricant compared to R32, and their interfacial tension is more susceptible to pressure variation. Experimental data of solubility were correlated by the NRTL activity coefficient model with the maximum absolute deviations and the average absolute deviations of less than 5.83% and 3.47%, respectively. An empirical correlation has been introduced to accurately describe the interfacial tension of multicomponent mixtures, and their parameters were determined by the nonlinear optimization method. The maximum absolute deviations and the average absolute deviations of interfacial tension for R32/POE-68 and R1234yf/POE-68 mixtures are within 3.88% and 1.44%, respectively.