Critical Study of a Residual Viscosity Correlation of JOSSI: Mixture Hydrocarbons Case

Abstract

In Jossi et al. (1962), there is the common model of the viscosimetric behavior where the residual viscosity is represented by a polynomial function of 4th degree involving the reduced density. This study shows that JOSSI’s method depends on three main factors including the adjustment quality of the coefficients, the characterization of the pseudo-critical coordinates via the rules of mixing and the density determination by the equations-of-state. Accordingly, it is important to determine the suitable correlation coupling among viscosity, equation-of-state and mixing rules. Thus, the results obtained from the initial set of JOSSI coefficients have been compared with the new values, for five density determinations’ possibilities and for ten mixing rules, in order to estimate the pseudo-critical coordinates and the characteristics of the mixtures. The results of this paper reveal that the new set of coefficients gives a more precise representation on the hydrocarbon mixtures than the method of JOSSI. The results also show that the equation-of-state established by Peng D.X., Robinson D.B is not suitable to generate the density values. The use of equation-of-state induces more correct prediction of viscosity than the density’s experimental values. Moreover, only 4/10 of mixing rules seem to lead to the most appropriate results. Finally, the method of JOSSI seems to be especially interesting for the viscosities restitution of systems containing light and non-contrast paraffins, but it is not suitable for complex mixtures and heavy hydrocarbons.