Optimization of Biodiesel Production from Oils and Fats with High Free Fatty Acids

Abstract

Biodiesel may be cost effective if produced from low cost feedstock such as animal fats, restaurant waste oil and frying oil, which contains high amount of free fatty acids (FFA). In the present work, two-stage transesterification process was used to convert a mixture of 75% restaurant waste oil and 25% pig fat oil (PFO) into restaurant waste oil pig fat methyl ester (RWOPFME). Different amounts of methanol (25, 30, 35, 40, 45 and 50% by vol.), alkaline catalyst (NaOH) concentrations (0.3, 0.5, 0.7, and 0.9% by wt.), reaction temperature (55°C, 60°C and 65°C) and reaction time (90, 120 and 150 min) were selected for the transesterification process in order to optimize the experimental conditions for maximum biodiesel yield. Amount of H 2 SO 4 (1.5 ml) was kept constant. Maximum yield (80% by vol.) at optimized process parameters such as methanol (40%), NaOH (0.3 g), reaction temperature (65°C), reaction time (90 min) and H2SO4 (1.5 ml) was obtained.