A Group Contribution Pseudocomponent Method for Phase Equilibrium Modeling of Mixtures of Petroleum Fluids and a Solvent

Abstract

We present a group contribution pseudocomponent (PC) method for mixtures of petroleum fluids and a solvent based on the characterization method (CM) for petroleum fractions and the predictive Peng–Robinson 1978 (PPR78) model. The objective of this study is to model the phase equilibrium of crude oil and a solvent consisting of one or multiple pure components. We develop a structural analysis of crude oil to bridge the CM and the PPR78 model, which predicts the temperature-dependent binary interaction parameters (BIP) among the PCs and pure components. The predicted results using our method agree well with experimental data for mixtures of oil sand bitumen and propane, CO2, or water. The approach is applicable to phase equilibrium predictions of mixtures of crude oil and water over a wide range of temperatures (273–644 K or higher as reasonable extrapolations) and pressures (4 kPa–26 MPa).