Phase equilibria modeling of biodiesel related mixtures using the GCA-EoS model

In this work, a group-contribution equation of state that takes into account association effects (GCA-EoS) is extended to model the phase behavior of fatty esters (biodiesel) in binary mixtures with glycerol, alcohols and water and ternary mixtures with glycerol and methanol. A new associating group (glycerol hydroxyl group: OHGly) was defined to take into consideration the association effects in the glycerol molecule. Self-association of methanol, water and glycerol and cross-association between methanol–glycerol, alcohol–ester, water–ester and glycerol–ester groups were considered. New pure-group, binary interaction and association parameters have been determined. The correlations and predictions of the model are found in acceptable agreement with selected experimental data reported in the literature.