Liquid density and bubble point measurements of R-290+POE ISO 32 lubricating oil mixtures between 283.15 and 343.15 K.

This study presents experimental analyses of liquid density and bubble-point pressure for binary mixtures of R290 and POE ISO 32 lubricating oil between 283.15 and 343.15 K. Using a variable-volume synthetic apparatus, bubble-point pressures were measured for mixtures with R-290 mol fractions ranging from 0.2149 to 0.8140. Only vapor-liquid phase equilibrium (complete miscibility) was observed across all compositions and temperatures investigated. In addition, liquid densities were measured at temperatures between 283.15 and 343.15 K at pressures up to 5 MPa using a vibrating-tube densimeter. The experimental data were correlated using the PatelTeja-Valderrama (PTV) and Perturbed Chain-Statistical Associating Fluid Theory (PC-SAFT) equations of state (EoS). For the bubble-point pressure calculations, the absolute average relative deviation (AAD) was 3.28 % and 6.09 % for the PC-SAFT and PTV EoS, respectively. For the density predictions, the corresponding AAD values for the PC-SAFT and PTV EoS were 0.94 % and 6.94 %, respectively.