Viscosities of Organic Liquids: Predictions and Correlations for Some Binary Systems

DOI: 10.5176/2301-3761_CCECP18.29

Authors: M. Mehedi Hasan Rocky1, Shamim Akhtar, M. Nur Hossain

Abstract:

Thermodynamics, and transport properties have long been in use in understanding molecular interactions of liquids and their mixtures. A prior knowledge of thermodynamics and transport properties of pure liquids/multi-component mixtures is extremely important at early stages of designing chemical processes. Viscosity is considered as one of the most significant transport properties from the scientific point of view and for various chemical applications. With an increased popularity of process and reservoir simulators, there is always an acute need for consistent, reliable as well as accurate predictive methods for viscosity calculations. The present study reports on dynamic viscosities predicted for liquid mixtures of 18 different binary systems in the entire range of composition and at different temperatures, involving various types of alcohols, aromatics, ketones as well as acetonitrile. Computations were performed following two different approaches. The first methodology corresponded to correlative models of McAllister, whereas the second one belonged to a predictive method, viz. the UNIFAC-VISCO model. Furthermore, to investigate its predictive capability, the UNIFAC-VISCO model has also been tested critically by considering of group interaction parameters belonging to two different categories: (a) αnm of original UNIFAC-VISCO and (b) βnm of the UNIFAC-VLE. Consideration of βnm parameters in line with αnm has further led to easier predictions of both the dynamic and the kinematic viscosities of various organic liquids in a wider range. Also, from our experimental viscosity data of the acetonitrile + n-butanol, the αnm parameters corresponding to CH3CN with alcoholic –CH3, –CH2 and –OH groups were determined anew, availability of which would contribute further in extending the range of applicability of the conventional UNIFAC-VISCO model.

Keywords: UNIFAC-VISCO; viscosity; McAllister; group interaction parameter. I