(Vapor + Liquid) Equilibrium for Mixtures Ethanol + Biodiesel from Soybean Oil and Frying Oil

Abstract

In order to provide new isobaric vapor−liquid equilibrium (VLE) data for ethanol-biodiesel systems, experimental boiling points for mixtures of ethanol + biodiesel from soybean oil (SB) and frying oil (FB) were measured. UNIFAC and NRTL models were used to predict and correlate the data, in order to better represent the VLE in process simulation. VLE data were measured with a Fischer type ebulliometer. Reliability and reproducibility were evaluated with VLE data for ethanol + water system at 101.32 kPa. These data also proved to be thermodynamically consistent based on the area test. The boiling temperatures for ethanol + biodiesel systems agreed with other results reported at same pressure for SB and for biodiesel from sunflower seed oil (SSB). The thermodynamic modelling using the NRTL model obtained lower AAD values than those from UNIFAC, assuring better safety in the design and simulations steps of a biodiesel production plant.

Droplet evaporation of alcohol-biodiesel blends

“…to determine the surface tensions of 78 different biodiesel blends with an average absolute relative deviation of 1.86% [40]. The UNIFAC method has been successfully used to model the vapour liquid equilibrium behaviour of a biodiesel-ethanol system [26]. The UNIFAC method was also able to calculate the liquid-liquid equilibria of biodiesel-glycerol-methanol and biodiesel-glycerolethanol systems with a root mean square deviation of 6.2% and 8.8% respectively [41].…”

“…Individual FAME compounds mixed with ethanol, specifically methyl laurate, methyl myristate, and methyl oleate, have had experimental vapour liquid equilibrium results taken at a pressure of 1 atm [23]. Experimental vapour liquid equilibria measurements have also been taken for biodieselethanol systems at pressures of 100 kPa [24], 91.4 kPa [25], and 101.32 kPa [26].…”

“…The vapour liquid equilibrium has also successfully been numerically modelled for biodiesel and ethanol system using the UNIFAC method and the NRTL method [26].…”