On the relationship among isopleths, three-phase lines and two-phase constant phase fraction lines for binary systems (T252)

MOLINA, MATÍAS J.; CISMONDI, MARTÍN; RODRIGUEZ-REARTES, SABRINA BELÉN; ZABALOY, MARCELO SANTIAGO

Nova Friburgo

Congreso; X Congresso Brasileiro de Termodinâmica Aplicada (CBTermo 2019); 2019

Universidade do Estado do Rio de Janeiro (UERJ)

When working with models of the Equation of State (EoS) type, it is possible to compute, for binary systems, the univariant fluid phase equilibrium lines [critical and liquid-liquid-vapor (LLV) lines] before computing specific sections of the thermodynamic surfaces, such as isotherms, isobars or isopleths (IPs). An IP is defined by a set global composition z1, and it is made of the phase envelope (PE) and of the heterogeneous region (HR). The PE is generally made of dew lines, bubble lines and cloud point lines (liquid-liquid equilibrium). The HR is characterized by proper segments of the LLV line/s, and by two-phase lines of constant, e.g., phase mole fraction. In particular, already computed LLV lines have valuable information for the further computation of an IP of set global composition z1. In this case, a criterion is needed for detecting the segments of the LLV line/s which should be part of the HR of the IP to be computed. One such criterion is proposed in this work Through the application of this criterion it is possible to automatically detect the LLV points that will be located on the PE of the IP, and the LLV points that must appear within its HR. Furthermore, it is also possible to establish all LLV points that are endpoints of the segments of which a two-phase line of set phase mole fraction is made of.