280211 Determination of Binary Parameters of Liquid-Liquid Equilibrium for Biodiesel + Glycerol + Ethanol Systems Using Local Composition Models

Monday, October 29, 2012: 1:36 PM
413 (Convention Center )
Nathan Sombra1, Frederico do Carmo1, Rílvia Santiago-Aguiar2 and Hosiberto de SantxAna1, (1)Chemical Engineering Department, Universidade Federal do Ceará, Fortaleza, Brazil, (2)Chemical Engineering Department, Universidade Federal do Ceará, Fprtaleza, Brazil

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.

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See more of this Session: Thermodynamics of Energy Systems
See more of this Group/Topical: Engineering Sciences and Fundamentals