Solubilities of 3, 3, 3-trifluoropropene in pentaerythritol tetrahexanoate and pentaerythritol tetraoctanoate from 278.15 K to 343.15 K at pressures to 1 MPa

Abstract

Due to the very low GWP and good thermodynamic properties, 3, 3, 3-trifluoropropene (R1243zf) was considered as a promising substitute for R134a. The phase behavior of R1243zf with lubricant oils is essential for the optimization of the refrigeration cycle. In this work, the solubility of R1243zf in pentaerythritol tetrahexanoate (PEC6) and pentaerythritol tetraoctanoate (PEC8), which are the two pure components of polyol ester (POE) oil, was determined at temperatures from 278.15 K to 343.15 K and pressures up to 1.0 MPa using isochoric saturation method. The experimental data were regressed by means of non-random two liquid (NRTL) model and Krichevsky-Kasarnovsky (K-K) model, respectively. Both of the two models present good correlation results with the absolute average relative deviations lower than 3.0 %. Moreover, the solubilities of different hydrofluoroolefin refrigerants (R1234yf, R1234ze(E) and R1243zf) in the studied PECs were compared. Results show that the molar fraction of HFOs dissolved in the same PECs follows: R1234ze(E) > R1243zf > R1234yf. In addition, the dissolution thermodynamic properties including the mixing enthalpy, mixing Gibbs energy and mixing entropy of R1243zf in PEC6 and PEC8 were calculated according to experimental solubility data and the NRTL model, and the dissolution process was analyzed.