Ultrasonic assisted biodiesel production

Abstract

One of the biggest hurdles in the production of biodiesel is the high production cost compared to petroleum-derived diesel. Even though the mechanical agitation utilised during biodiesel production is effective, it is energy intensive and costly. In this study ultrasonic assisted biodiesel production has been considered as a more economical alternative. The optimum transesterification reaction conditions were investigated using sunflower oil as a feedstock, methanol (MeOH) as the alcohol, along with potassium hydroxide (KOH) as catalyst. The transesterification reactions were carried out in an ELMA® ultrasonic bath. The reactions were completed at different ultrasonic frequencies, reaction times, alcohol to oil molar ratios and catalyst loading weights. Both Gas Chromatography (GC-MS) and FT-IR Spectroscopy analyses were used to determine the fatty acid methyl esters (FAME) content of the resulting biodiesel. The optimum ultrasonic assisted biodiesel production reactions were found to be 60ºC, 35 kHz, an alcohol to oil ratio of 9:1, a catalyst loading of 0.5 wt%, with a reaction time of 50 minutes. The resulting biodiesel FAME yields at these conditions were higher than 96.5 wt%. The reduction in reaction time due to the ultrasonic effect reduced the production cost by about 7% if compared to the traditional mechanical agitation