Prediction of Density and Viscosity of Bitumen Using the Peng-Robinson Equation of State

Density and viscosity are important quantities required in engineering design for production, fluid transportation, and processing. However, there is no satisfactory theory for the calculation of these properties for bitumen. The principal objective of this paper is to obtain thermodynamic models to predict the density and viscosity of bitumen on the basis of the translated version of the Peng-Robinson equation of state. In the density calculation, a consistent correction to improve the liquid-phase volume estimation was applied. The density model evidenced a small percent average absolute error regarding experimental data (less than 1%). The model for viscosity was based on a modification of the Enskog's equation. This modification allowed the prediction of bitumen viscosity using an equation of state along with a substance- and temperature-dependent parameter; this approach showed good accuracy with respect to experimental data. An important advantage of these models is the possibility of estimating viscosities at different pressures.