Volatility of Blended Fuel of Biodiesel and Ethanol

Abstract

The transesterification of sunflower seed oil was carried out in supercritical ethanol without using any catalyst. Ethyl esters of vegetable oils have several outstanding advantages because ethanol is derived from agricultural products and is renewable and biologically less objectionable in the environment. On the other hand, because of lower volatility, ignition delay and combustion problems could occur when ethyl esters are used. In the present work, ethanol is added to enhance the vapor pressure of biodiesel. The bubble-point pressures of mixtures of biodiesel and ethanol as a function of temperature were measured by comparative ebulliometry with inclined ebulliometers. Experimental data of vapor pressures and equilibrium temperatures were correlated by the Antoine equation. The bubble-point lines of pressure versus the composition at different temperatures and the temperature versus the composition at different pressures were obtained. It is found that the mixtures of biodiesel and ethanol have visible positive deviations from Raoult's law. The addition of ethanol has a critical effect on the vapor pressure of fuels.

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

“…These results demonstrate that the VLE data trend agrees with the reported data plotted in ethanol mass fraction in the liquid phase (w1). Despite the small differences in pressure, the temperature values are so close as to be in agreement with the small temperature changes found when the pressure was increased from 64.4 to 91.4 kPa in the VLE data, as reported by Silva et al [11] Furthermore, temperatures for the VLE data were expected to be lower than those studied by Guo et al [15], since the SSB was composed of ethyl esters, while the SB adopted in our work and by Silva et al [11] were composed of FAME. [26] at same pressure and (b) with VLE obtained by NRTL model.…”

“…These data were compared with the VLE data from mixtures ethanol + SB and ethanol + biodiesel from sunflower seed oil (SSB) reported by Silva et al [11] and Guo et al [15] at 91.4 kPa and 100 kPa, respectively, as shown in Figure 3a and 3b. These results demonstrate that the VLE data trend agrees with the reported data plotted in ethanol mass fraction in the liquid phase (w1).…”

“…The composition of fatty acids as specified by Silva et al [11] and Alcantara et al [28] for SB and FB, respectively, were used to calculate the vapor pressure of the alkyl ester mixtures, as shown in Table 3. [11], [15].…”

“…In addition, the use of ethanol instead methanol is encouraged since it is a renewable fuel and also lesser toxic. Furthermore, few studies have reported on the use of VLE data for ethanolbiodiesel systems close to ambient pressure [6], [11], [15]. These studies are not only important for a better representation of the VLE data in distillation columns and flash drums, but also as they show that a blend alkyl estersethanol can be used as a fuel to reduce the ignition delay and combustion problems due to low ethanol vapor pressure [15].…”

Determinação Experimental Do Equilíbrio Líquido-Vapor Da Mistura Pseudo Binária Biodiesel E Etanol

“…Os dados experimentais obtidos foram avaliados e comparados com os dados da literatura (GUO et al, 2007) mediante descrição gráfica da T-x 1 , baseado nos princípios de equilíbrio líquido/vapor do sistema etanol (1)-biodiesel (2). No entanto, mesmo considerando a comparação feita, é fundamental registrar que os dados da literatura (GUO et al, 2007) foram obtidos experimentalmente a partir de pressões abaixo da pressão atmosférica, diferentemente da pressão utilizada neste trabalho.…”