Modeling equilibria involving solid and fluid phases for light n-alkane + wax binary systems

TASSIN, N.G.; RODRÍGUEZ REARTES, SABRINA BELÉN; ZABALOY, MARCELO S.; CISMONDI DUARTE, M.

Conferencia; EQUIFASE 2018: XI Iberoamerican Conference on Phase Equilibria and Fluid Properties for Process Design; 2018

Theprecipitation of waxes in reservoir fluids, which can also lead to depositionon tubing and different equipment, is the result of a supersaturation of thefluid, according to its composition and conditions of temperature and pressure.To avoid this phenomenon it is required to know the phase equilibrium betweenthe solid phase containing paraffins (n-alkanes typically in the C20-C50range), and the fluid phase/s (liquid or gas). An appropriate model torepresent the different solid-fluid equilibria of a multicomponent system (suchas reservoir fluids) should be able to reproduce the experimental behavior ofthe binary subsystems that compose it. To model this phenomenon, an existing approach[1]  uses an equation of state (EoS) torepresent the fluid phases together with an additional expression (AE) for thefugacity of the precipitated n-alkane as a pure solid (Eqs 1-2).