Biodiesel production from butter factory effluent

Abstract

The increase in energy demand coupled with the depletion of fossil fuels has increased the need for renewable and sustainable energy sources. Butter waste effluent was identified as a possible feedstock for biodiesel. The effects of the temperature, alcohol to oil molar ratio, catalyst concentration and the reaction time were investigated to determine the optimal reaction conditions of the transesterification reaction. The optimal reaction conditions according to the results were 50°C, 6:1 alcohol to oil molar ratio, 1.0 to 1.2 wt% catalyst loads and a reaction time of 60 to 90 min. Different methods of purification were investigated in an attempt to decrease waste of a biodiesel plant, including the dry washing agents, Magnesol® D-SOL^TM and Purolite® PD-206. The Magnesol® D-SOL^TM was found to be the optimum method for lowering the water content and the acid value of the fuel. The biodiesel was tested according to the SANS 1935:2011 standard and did not meet the requirements of the standard with regard to flash point, sulphur content, carbon residue, oxidation stability, free glycerol, total glycerol and cold filter plugging point. In order for the biodiesel to be suitable for commercial use, it should be blended with mineral diesel.

Keywords: Transesterification, butter waste, biodiesel purification, reaction kinetics.