Tesis
Uso de cenizas volantes secas modificadas obtenidas de residuos de la industria papelera como catalizador heterogéneo para la producción de biodiesel a partir de aceite usado de cocina
Autor
Espitia Castañeda, Yesica Daniela
Santos García, Natalia
Institución
Resumen
Most of the world's energy is supplied by fossil fuels which contributes to environmental
pollution by the emission of greenhouse gases, such obtaining biofuels has become one of
the alternative energy sources that reduce environmental impact and are economically
profitable. Within this new alternative exist the biodiesel that can be obtained from vegetable
oils or animal fats. In the present investigation the biodiesel production from waste cooking
oil (WCO) and methanol was evaluated using as a heterogeneous catalyst dry fly ash
obtained in the combustion processes of the Portuguese paper industry, these ashes were
impregnated with Sulfuric Acid (H2SO4) and subsequently it was calcined in order to carry
out the simultaneous esterification and transesterification reactions. In the first place, the
raw material characterization was determined by some oil physicochemical properties such
as: acid value, acidity percentage, saponification index, viscosity, density and humidity;
while the catalyst was characterized by different techniques such as X-ray diffraction (XRD),
scanning electron microscopy (SEM), X-ray energy dispersion spectrometry (EDX), Fourier
transform infrared spectroscopy (FTIR), BET method (BET specific surface area), BJH
method (diameter and pore volume) and Hammett indicators (acid sites and basic sites).
The reactions were carried out in a glass batch reactor of 250 mL at a temperature of 60 °C,
600 revolutions per minute, a reaction time of 3 hours and a catalyst concentration of 10%
w/w respect to the oil used taking into account two levels and three factors: methanol:oil
ratio (6:1 and 12:1), type of oil charge (WCO-1 and WCO-2) and sulfuric acid concentration
in the catalyst (0.025 and 0.050 molar). Subsequently, the yield of fatty acids methyl esters
(FAMEs) was quantified through gas chromatography and the conversion of free fatty acids
(FFA) was evaluated by acid number, additionally the loss in catalytic activity was studied
due to the catalyst reuse in three cycles. The results obtained showed that the maximum
yield to FAMEs was 5.96% using waste cooking oil with lower acid value (AUC-1), the
sulfonated dried fly ash (CVS-SC-0.050) and a methanol:oil molar ratio 6:1 for all the factors
and levels evaluated with a FFA conversion of 90.62%. The catalyst evaluated in the reuse
cycles showed a high catalytic activity obtaining yields to FAMEs of 66.66% and 63.98%.