Effect on the Use of Ultrasonic Cavitation for Biodiesel Production from Crued Jatropha Curcas L. Seed Oil with a High Content of Free Fatty Acid

A typical way to produce biodiesel is the transesterification of plant oils. This is commonly carried out by treating the pre-extracted oil with an appropriate alcohol in the presence of an acidic or alkaline catalyst over one or two hours in a batch reactor. Because oils and methanol are not completely miscible. It has been widely demonstrated that low-frequency ultrasonic irradiation is an effective tool for emulsifying immiscible liquids. The objective of this research is to investigate the optimum conditions for biodiesel production from crude Jatropha curcas oil with short chain alcohols by ultrasonic cavitation (at 40 kHz frequency and 400 Watt) assisted, using two step catalyst method. Usually, the crude Jatropha curcas oil has very high free fatty acid which obstructs the transesterification reaction. As a result it provides low yield of biodiesel production. In the first step, the reaction was carried out in the presence of sulfuric acid as an acid catalyst. The product was then further transesterified with potassium hydroxide in the second step. The effects of different operating parameters such as molar ratio of reactants, catalyst quantity, and operating temperature, have been studied with the aim of process optimization. It has been observed that the mass transfer and kinetic rate enhancements were due to the increase in interfacial area and activity of the microscopic and macroscopic bubbles formed. For example, the product yield levels of more than 90% have been observed with the use of ultrasonic cavitation in about 60 minutes under room temperature operating conditions.