Produção de biodiesel utilizando tensoativo e cascas de ovos de galinha

Abstract

Biodiesel is considered an alternative source of fuel, that consists of fatty acid alkyl ester. Industrially, transesterification is the route most used to produce it, that is a chemical reaction between triglycerides and alcohol, with a homogeneous or heterogeneous catalyst. Surfactants are substances that have two parts, one hydrophilic, and the other hydrophobic and are characterized by their tendency to adsorb surfaces and interfaces. This work aims to evaluate the use of surfactant Nonylphenol ethoxylated in a transesterification reaction of soybean oil with methanol, catalyzed by the calcium oxide (CaO) synthesized from chicken eggshell. Two experimental factorial design were performed, both with the addition of three central points. In the first one, 22, it was evaluated the ethoxylation number and the surfactant concentration. In the second one, 23, with 1% of Nonylphenol with 7 moles ethoxylated (NP7EO). It was evaluated the reaction time, catalyst concentration and methanol to oil molar ratio. In addition, the kinetic constants for the system with and without the presence of NP7EO were determined. The ethoxylation number and its concentration did not influence significantly in the biodiesel conversion. In the factorial design 23, the predicted model using 1% de NP7EO was significant in the biodiesel conversion, the maximum was 98,95%, with 5% of CaO, methanol to oil molar ratio of 7/1, 65 ° C, 3 hours reaction. In the study with and without NP7EO, the kinetic constants, 0,012 min-1 and 0,0089 min-1, were obtained, respectively, and the reactions were shown to be pseudo-first order. Furthermore, the results have shown higher conversions in the reactions with NP7EO. Thus, the surfactant influenced better biodiesel conversions and improved the transesterification reaction rate, increasing its velocity. Probably due to its ability to improve the dispersion between the phases of the mixture reagents.