Significance of equation of state and viscosity on the thermodiffusion coefficients of a ternary hydrocarbon mixture
Seshasai Srinivasan and M. Ziad Saghir
An accurate thermodiffusion model is very critical in the petroleum industry for determining the hydrocarbon composition in an underground reservoir. In this paper, investigations have been made to understand the significance of the appropriate equation of state as well as the fundamental property of the mixture component, viz., viscosity. For the former, the performance of Peng Robinson and Perturbed Chain Statistical Association Theory equation of states have been compared for six different ternary mixtures. The Peng Robinson equation of state was found to be more accurate. The latter had shortcomings due to the oversimplification of the model resulting in inaccurate prediction of the thermodiffusion coefficients of the respective components in the ternary mixtures. Significance of accurate estimates of viscosity for thermodiffusion calculations was also studied. It was found that small changes in viscosity have a significant influence on the thermal diffusion coefficients.
Keywords: Thermodiffusion, Irreversible Thermodynamics, Equations of State, Viscosity.