Waste Frying Oil Transesterification Treated by Steam Drag Method

Abstract

Demand for diversified biodiesel feedstocks is high and increasing, but few are viable for large-scale production, and many of those selected compete with other sectors of the chemical industry. To improve energy and environmental sustainability, fatty acids from waste oils that are improperly disposed of and pollute the environment can be used for transesterification reactions. However, they need treatment to achieve high conversion rates. In this context, the aim of this work was to perform and analyze the treatment of residual frying oil with the evaporation and entrainment process, aiming at its use as raw material to obtain biodiesel (methyl esters) by a transesterification reaction. The physicochemical properties of the residual oil after treatment were characterized by moisture content, pH and the acidity, saponification, iodine, and peroxide index. The conversion rate of the residual oil to methyl esters was determined by 1H NMR analysis. After the treatment, the method of analysis of variance showed that the oil obtained a significant reduction of the saponification, iodine, peroxide and acidity indexes, being the acidity reduced from 9.36 to 7.85 mg KOH g-1. The moisture content of 0.733% and elevation of pH to 8.0. The conversion rate of fatty acid biodiesel of residual oil was 79.3 %, lower value of standards norms (ASTM, 2005; EN, 2008; ANP, 2014), showing that the assigned methodology for frying residual oil is inefficient in biodiesel production.