(118d) Determination of Binary Parameters of Liquid-Liquid Equilibrium for Biodiesel + Glycerol + Ethanol Systems Using Local Composition Models

In the last decades, biodiesel has been considered an alternative fuel for diesel engines, due its characteristics, e.g., non-toxicity, renewability, ignition properties, and almost zero sulfur content. During biodiesel production a liquid-liquid equilibrium (LLE) among biodiesel, glycerol, and alcohol may occur. For this reason, the knowledge of LLE data is essential for design, unit operations processes, and process modeling. A set of data on LLE (biodiesel + glycerol + ethanol), taken from different sources of the literature and also from experimental measurements determined by our research group was used in this work. A total number of 69 tie-lines have been listed. These data were modeled by using two local composition models (NRTL and UNIQUAC equations). Binary parameters for biodiesel + glycerol + ethanol systems have been obtained from these data. Additionally. a set of new binary parameters for glycerol-ethanol has been obtained for biodiesel + glycerol + ethanol systems. Ternary LLE diagrams were constructed and it could be observed a satisfactory behavior by comparing experimental and calculated compositions and tie-lines, with a global root mean square deviation of 1.13 % and 1.66 % for NRTL and UNIQUAC models, respectively. Consequently, biodiesel + glycerol + ethanol systems can be represented by using both models tested.