Biodiesel from Palm Fatty Acid Distillate (PFAD) and its nature of oxidative stability

Abstract

Palm Fatty Acid Distillate (PFAD) is relatively cheap and its utilization does not compete with food needs. The availability of PFAD in Indonesia is considered sufficient as a supply of raw material for making biodiesel. This study aims to make biodiesel from PFAD in accordance with SNI 7182-2015 and to determine the best concentration of antioxidant additions. The research stage begins from making biodiesel through esterification reaction at 60 °C for 1 hour and continues with determination of each biodiesel Induction Period (IP) using a modified Rancimat device. PFAD used consisted of 99.85% mole total free fatty acids, consisting of 88.35% mole of saturated fatty acids and 11.5% mole of unsaturated fatty acids. Based on the research results, biodiesel produced meets SNI 7182-2015 from parameters of density, viscosity, alkyl ester content, and oxidative stability but does not fulfil the requirement of water content and value of acid numbers. The average IP in pure biodiesel has reached the minimum standard of 6 hours, which is 6.15 hours. Additions of six antioxidant Z concentrations (0.1, 0.3, 0.4, 0.5, 0.7, and 0.9 ppm) resulted in 0.1 ppm as the best antioxidant concentration in increasing IP to become 11.05 hours.