Obtención de biodiesel a partir de aceite vegetal reciclado mediante transesterificación aplicando NaOH ó KOH como catalizadores

Abstract

The environmental impact due to the use of fossil fuels has led to the research of new renewable energy sources and the generation of biofuels. So in recent years the obtaining of biodiesel from recycled vegetable oil has been studied. Currently, the Telecommunications, Drinking Water, Sewerage and Sanitation Company of Cuenca (ETAPA EP) is responsible for the collection and storage of this waste. An alternative is to use this waste as raw material. Therefore, this work aims to obtain biodiesel from recycled vegetable oil by transesterification applying NaOH or KOH as catalysts. First, the recycled vegetable oil was subjected to a pretreatment of filtration, washing and drying and when determining the physicochemical properties it was obtained: a density of 0.9422 ± 0.018 g/mL, 0.3114 ± 0.003 % of free fatty acids, 0.3102 ± 0.003mg KOH/g of acidity index, humidity of 0.02422 ± 0.021%, viscosity of 39.8700 ± 0.010 mm2/s and 30.2334 % oleic acid C18:1. To obtain biodiesel, the transesterification reaction was carried out at 55 °C, 1.5h, 350 rpm and molar ratio 6:1 alcohol / oil. In the case of catalysts, we worked with concentrations of 0.5 and 1% of both NaOH and KOH. Subsequently, its main physicochemical properties were determined and according to the ANOVA analysis of variance, post hoc KOH obtained a higher yield (93.19 ± 1.6689% and 93.31 ± 3.0218% at 0.5% and 1% concentrations respectively). When analyzing the cost, accessibility to the reagent and performance, it was determined that the KOH at 0.5% turns out to be optimal in obtaining biodiesel. This biofuel has the following properties: density of 0.8807 ± 0.0011 g/mL, viscosity of 4.6936 ± 0.07680mm2/s, acid number 0.3550 ± 0.0856 mg KOH/g and corrosion 1a. They comply with the Standard of the American Society for Testing and Materials (ASTM) D6751, Ecuadorian Technical Standard of the Ecuadorian Institute for Standardization (NTE INEN) 2482 and European Standard (EN) 14214. In addition, its calorific value was 39726 ± 364.91 J/g. However, the percentage of FAMEs of 93.0840 ± 0.9571%, did not meet the minimum of 96.5% established in the EN 14214 and NTE INEN 2482 standards.