Transesterification of vegetable oil with ethanol using different catalysts

Abstract

An experimental investigation has been carried out to produce bio-diesel from Vegetable oil (Soybean oil) with ethanol using three different catalysts (egg shell, NaOH and KOH) through transesterification reaction. Though, recently, heterogenous catalyst is being considered to be a cheaper alternative to homogenous catalyst, homogenous catalysts are currently mostly used to produce biodiesel. Heterogenous transesterification is considered to be a green and cheaper process but it generally requires more severe operating conditions and performance of heterogenous catalysts is generally lower than that of the commonly used homogenous catalysts. This study seeks to address this problem by studying the production of biodiesel using eggshell as heterogenous catalyst. Fatty acid ethyl ester was produced by transesterification of Vegetable oil and ethanol using calcined eggshell as a heterogenous catalyst and NaOH as well as KOH as homogenous catalysts. To optimize the process, some important variables such as reaction temperature, molar ratio of ethanol to oil and mass weight of catalyst were selected and studied. At the following conditions: 338K of reaction temperature, ethanol to soybean oil ratio of 9:1 and 1 mass wt.% of catalyst, an optimum fatty acid ethyl ester yield of 92% was obtained, indicating that eggshell have the potential of being used as a heterogenous catalyst for the production of fatty acid ethyl ester from Vegetable oil. Based on the experimental result it was found that the values of density, higher heating value and kinematic viscosity of produced biodiesels were more or less consistence with the ASTM standard biodiesel. Calorific values of biodiesels were lower than that of the diesel fuel. Densities of the biodiesels were found to be higher than that of the petroleum diesel. The flash points of the biodiesels had lower value than that of the ASTM standard biodiesel and petroleum diesel.