Ultrasound assisted in situ production of biodiesel from rice bran

Ultrasound was applied to the in situ production of biodiesel from rice bran to increase the content and yield of fatty acid methyl esters (FAME) in the product. The effects of ultrasound, temperature, reaction time and initial FFA content in the bran on the FAME content and yield were investigated. At a reaction temperature of 60°C and amount of H₂SO ₄=1•5% methanol (v/v), ultrasound was found to be effective in increasing FAME content and yield. Compared to the results from mechanically stirred in situ methanolysis of rice bran with low FFA content (13•27%), applying ultrasound increased FAME content and yield by 38•46 and 44•91% respectively, after 1 h of reaction. If ultrasound was applied to the in situ methanolysis without stirring, the increase in FAME content and yield after 1 h of reaction were 32•02 and 29•62% respectively, as compared to the results of in situ methanolysis with stirring only.