Robust and efficient determination of saturation pressure from constant mass expansion data

Abstract

This article presents an improved method for the determination of saturation pressure from pressure‐volume data of constant‐mass expansion (CME) for hydrocarbon mixtures. The conventional methods rely on the direct observation of an incipient phase and/or the change in total compressibility of the fluid sample near the saturation pressure in CME; however, they are unreliable for volatile oils, gas condensates, and near‐critical fluids. The method developed in this research is to capture the expansion behavior of the overall fluid through the attraction and covolume parameters of the Peng–Robinson equation of state. The reliability of the new method is demonstrated by comparing it with the conventional methods in the case studies using 59 different fluids. It was the only method that could reliably identify saturation pressures for five volatile oils, 11 gas condensates, and one near‐critical fluid among the datasets tested.