Characterization of the Heterogeneous Region of Computed Solid-Fluid Equilibrium Isopleths

S.B. RODRIGUEZ-REARTES; M.S. ZABALOY

ALICANTE

Conferencia; X IBEROAMERICAN CONFERENCE ON PHASE EQUILIBRIA AND FLUID PROPERTIES FOR PROCESS DESIGN (EQUIFASE 2015); 2015

UNIVERSIDAD DE ALICANTE - ALICANTE ESPAÑA

The phase behavior of binary systems made of CO2 and an organic compound having a relatively highmolecular weight is of interest in varied applications, e.g, Refs [1,3]. Within the ranges of conditionsof interest, these systems may present fluid-fluid (FFE), solid-fluid (SFE), liquid-liquid-vapor (LLVE)and solid-fluid-fluid (SFFE) equilibria. Typically, transition pressures (temperatures) are measured atset temperature (pressure), and set overall composition (isopleths), through the synthetic method,covering a temperature (pressure) range. The result is a set of measured segments of isopleth phaseenvelopes, eventually together with segments of three-phase equilibrium lines in the pressuretemperaturespace. Appropriate models for these complex systems may be useful to interpolate andextrapolate experimental information, and to study possible patterns of phase behavior. One suchmodel has ben used in Refs [1] to [3]. In particular, in Ref [1] the calculated isopleths included thephase envelope and the appropriate segments of a SFFE line, for the system carbon dioxide +medroxyprogesterone acetate; while in Ref [3], for the sytem CO2+Mitotane, only phase envelopeswere computed. In both cases [1,3], the phase envelopes included SFE and FFE segments. Thesystems in Refs [1] and [3] present retrograde behavior. A more complete characterization of thecontribution of the SFE to isopleths can be done by computing lines of constant solidified fraction.Thus, the objective of the present work is to study the heterogeneous region of computed solid-sluidequilibrium isopleths of binary aysmmetric systems, by resorting to calculated constant solidfiedfractioncurves.[1] L.F. Pinto, S.B. Rodriguez-Reartes, M.L. Corazza, V.F. Cabral, P.H.H. de Araújo, E.H. Madureira, M.S.Zabaloy, L. Cardozo-Filho. Fluid Phase Equilib. 349 (2013) 1?11.[2] S.B. Rodriguez-Reartes, M. Cismondi, M.S. Zabaloy. J. Supercrit. Fluids. 57 ? 1 (2011) 9-24.[3] W. M. Giufrida, S. B. Rodriguez-Reartes, C. G. Alonso, M. S. Zabaloy, V. F. Cabral, F. W. Tavares, L.Cardozo-Filho. J. Chem. Eng. Data. 56-12 (2011) 4333-4341.