UJI KINERJA BIODIESEL DARI MINYAK BIJI KARET

Abstract

The increasing of national biodiesel-demand is not balanced with national production. Two of the reasons are using edible oil as feedstock and high production cost. Seventy percents of production cost comes from raw materials. Exploration of new crops and unexploited oil crops is needed to develop. We could use low-valued feed stocks such as unrefined vegetable oil, waste frying oil, or side product from vegetable oil hydrolysis, the fatty acids. Rubber seed is a potential feedstock for biodiesel in Indonesia, because it is one of the greatest producers in the world. Besides, rubber seed has high proportion of oil and has not been used optimally yet. By using a proper pre-treatment, we could produce high quality biodiesel. The aim of this third-year research is to produce biodiesel in the optimum condition, and analysed it with Engine Test Bed. The optimum conditions are: acid pre-treatment (using H2SO4 on 2.5% v/v as catalyst on the ratio of methanol to oil is 6:1, 60 oC), and the second step, alkaline (KOH) catalysed transesterification (which was processed in 1 hour, 2% catalyst, 50oC, on the ratio of methanol to oil is 6:1). Biodiesel was refined by settling, washing and adsorption. Based on previous research, we concluded that biodiesel from rubber seed oil with acid pre-treatment has lower carbon residue and higher flash point as the advantages. So, it was analyzed in an Engine Test Bed on this research. Biodiesel resulted better performance for B10 than petroleum diesel-fuel in lower rotation (< 2000 rpm), lower fuel-consumption and lower waste-gas flow rate.