PENGARUH KECEPATAN PENGADUKAN DAN SUHU REAKSI PADA ESTERIFIKASI MINYAK MENTAH DEDAK PADI BERKANDUNGAN ASAM LEMAK TINGGI

Abstract

Rice bran oil (RBO) derived from rice bran (RB) which could use as an alternative raw material for biodiesel production. Rice bran (dedak) are used as feed for poultry, pigs, and some dairy cattle because they are relatively cheap and do not require processing. The utilization of these oil further cheapen the cost of biodiesel and increased the economonic value of RB. The choice of RBO as a raw material for biodiesel due to the rice bran oil’s potentials. RBO is considered to be one of the most nutritious oils due to its favorable fatty acids composition and a unique combination of naturally occurring biologically active and antioxidant compounds (oryzanol, tocopherol, tocotrienol, phytosterol, polyphenol, dan squalene). The research emphazised on esterification reaction because of the rapid increase of FFA content in RBO after the milling of rice. Storage time of RB increased the FFA content. Mixing velocity dan time reaction was the other two variables which are affecting the esterification reaction. Those two variables are studied in this experiment.
 Experiment were designed to examine the mixing velocity and temperature reaction to the conversion of fatty acid methyl ester (FAME). Reaction condition 20:1 molar ratio methanol to FFA content and 5%-v/v catalyst (to the oil) was used in all experiments. Mixing velocity and time reaction was arranged as follows: 500, 750, 1000 rpm and 40, 50, 60oC, respectively. Research conducted in four parts: soxhlet extraction with n-hexane as a solvent; oil-solvent separation process; and the last step was esterification reaction. Reaction conducted on three neck round bottom flask equipped with magnetic stirrer, refluk condenser and thermometer. Crude product was separated first from unreacted methanol, glycerol, and catalyst prior to physical analyzed of biodiesel’s properties. Conversion of FAME was calculated from acid value difference, after and before reaction conducted.
 It was found that mixing velocity influenced the FAME conversion not significantly (specially in crude rice bran oil high fatty acid content esterification); increasing in temperature will increase the FAME conversion; kinetic reaction controlled by chemical reaction; and biodiesel product from this research already fullfill the requirements of Indonesian Standard of Biodiesel (FBI-SO1-03).