Physicochemical, transport and thermodynamic properties of saline solutions for process design using Padé approximants

Padé approximants are used to model physicochemical, transport, and thermodynamic properties of seawater for industrial applications. Sophisticated mathematical models to calculate saline solution properties are presented in the literature for applications in which very high accuracy is needed, such as oceanographic studies. Such accuracy is not necessary in the design and optimization of processes in which seawater is used, mainly in the mining industry (mineral concentration, hydrometallurgy, and refining processes). The properties studied are density, specific heat, osmotic coefficient, viscosity, thermal conductivity, surface tension, enthalpy, entropy, vapor pressure, latent heat of vaporization, and boiling temperature elevation. Padé approximants represent a useful tool in applied mathematics and have not been used to model saline solutions properties in the way presented here. Padé results are compared with Taylor series and simple polynomial expansions. The general models obtained are of rational type and give deviations similar to those provided by more sophisticated models presented in the literature.