Fatty acid methyl ester production from low value vegetable oil via alkaline catalyst

Abstract

Biodiesel was one of the most promising alternative renewable fuels to substitute the conventional fossil fuel. In this tropic, the production of biodiesel from low value waste vegetable oil (WVO) via alkaline catalyzed transesterification was studies. Characteristic of waste vegetable oil such as moisture content, acid value, and free fatty acid content and saponification value were studied. Its moisture content was determined to be 1.45 % in weight percentage. High acid value of WVO was 1.30 ± 0.02 mg KOH / g could cause soap formation in which lower the biodiesel yield. First acid pre-esterification step of WVO was carried out at methanol / oil ratio of 6:1, with using 1.0 % wt of sulphuric acid at reaction temperature of 50 ºC and time of 60 min. Second step, transesterification reaction was performed with using NaOH catalyst. The parameters in this study were molar ratio of methanol to oil and catalyst concentration. Methanol to oil molar ratio was prepared in 6:1, 9:1, and 12:1, whereas concentration of catalyst used was 0.5 %, 1.0 % and 1.5 % wt (based on oil weight). Highest biodiesel yield was 82.4 % in 6:1 molar ratio of methanol to oil, with 0.5 % of NaOH concentration. With achieved optimal condition, production of biodiesel process was designed using SuperPro Designer with a productive plant of approximately 1,268 metric tons per year. In this study, the achievement of economic evaluation for biodiesel production was done.