PENGARUH WAKTU PEMANASAN AWAL DAN UKURAN PARTIKEL TERHADAP PEROLEHAN MINYAK BIJI JARAK PAGAR (Jatropha curcas linn) DENGAN METODE PENGEPRESAN BERULIREffect of Preheating Times and Material Size on Jatropha (Jatropha curcas linn) Seed Oil Yield using Screw Press Method

Jatropha (Jatropha curcas linn) is a shrub whose seeds contain oil with a yield of about 30-40% and contains toxins which can not beeating, therefore it potential to produce biodiesel. Jatropha oil is a clear liquid, yellow, distinctive smell, no taste and no turbid even if stored for long periods. In this study, the oil is obtained by pressing method threaded (screw press).The objective of this researchwas studying the effect of material size and preheating time on Jatropha seed oil yield using screw pressing methode. The jatropha seeds were cleaned and the kernels were separated manually from the seeds. Then, jatropha seed was size reducted with various ± 2 cm, ± 1 cm, and < 1 cm. After that the jatropha seed was preheatead with various times 15 minute, 30 minute, and 45 minute. The following step was pressing it by using screw press, on 220 rpm. Moisture content of jatropha seed oil was identified in the range of 0,2-1,2%.The density of jatropha seed oil was obtained in the range of 0.896 to 0.912 g / ml. The viscosity was obtained between 17.33 to 19.51 cp, acid number jatropha seed oil gained between 3.03 to 3.9, jatropha seed oil saponification numbers were obtained between 188, 5 to 194.11. Keywords: Biodiesel, Jatropha, Screw pressing