15-15: Development of Biodiesel Production and Optimum Process Under Supercritical Fluid Conditions

The objective of this study was to develop a process for the production of biodiesel using supercritical characteristics of methanol and vegetable oil. The reaction was carried out in 300 mL batch scale supercritical reactor system under the condition of temperature 260°C~350°C and pressure 300~415 bar. Palm oil, commonly used in Southeast Asia, was used as feedstock. In the conventional process, acid or alkali catalysts are used for the biodiesel production. In this work, the supercritical characteristics of methanol without any catalyst were used to develop optimal non-catalytic supercritical biodiesel production. The FAME content obtained by supercritical process was 95.8wt%. This maximum yield was obtained at temperature of 340°C, pressure of 300 bar, reaction time of 10 min, and oil to methanol molar ratio of 1:50. The amount of saturated fatty acid (palmitic acid) in palm oil and soybean oil are 41.5wt% and 12.9wt%, respectively. When biodiesel production was carried out at pressure 415 bar and temperature 340°C in supercritical reactor, the biodiesel yield of palm oil and soybean oil were 95.5wt% and 84.1wt%, respectively. This result shows that feedstock contained high saturated fatty acids give more biodiesel yield in the supercritical process. The effect of moisture content and free fatty acid content on the biodiesel yield was tested in supercritical reactor using palm oil (upto 15wt%). The yield of biodiesel in the supercritical process was not affected by FFA content and moisture content within the range tested.