Optimization of ethyl ester production from arachis hypogaea oil

Abstract

Increased rate of use of fossil fuels have greatly polluted the earth through harmful by-products. Biodiesel is an attractive substitute to fossil fuel in compression ignition engine applications. In this research work, vegetable oil namely Arachis Hypogaea Oil (AHO) is used along with ethanol for biodiesel production. Since the amount of free fatty acid of AHO is 4.85%, two step transesterification process was adopted for biodiesel production. In the first step, 6:1 ethanol to oil ratio, 1% w/w concentrated H2SO4 with 60 °C process temperature and one hour process time were followed for esterification and the FFA value was found to be 0.86% after esterification. As ethanol is very rarely used for biodiesel production, optimization of transesterification process has been carried out using orthogonal array based experimental design. The four most influencing parameters, molar ratio of ethanol to oil, catalyst amount, process temperature and process time were considered for optimization. Ethanol to oil molar ratio of 9:1, 1% (w/w) concentration of catalyst, 90 min of process time and 70ºC temperature of reaction were found to be the optimal values of parameters for maximizing the yield of Arachis Hypogaea Ethyl Ester (AHEE) and the corresponding maximum yield was 95.49%. The biodiesel produced with optimum values of transesterification process parameters has been characterized and found to meet the biodiesel requirements of EN 14214 standards. Keywords: Arachis hypogaea, Transesterification, Optimization, Design of experiments, Orthogonal array, Biodiesel