Hielscher Ultrasonics demonstrates on
Biodiesel is made from vegetable oil or animal fat by a chemical conversion process called transesterification. Despite the use of heat, mechanical agitation and catalytic chemicals, this conversion takes approx. 4 to 6 hours. That is why, conventional biodiesel plants produce this renewable fuel in batches. First, the heated oil is mixed with alcohol and the catalyst in reactor batches using mechanical mixers for approx. one hour. After that, the mix is pumped into a separation tank where it takes another 4 to 6 hours until glycerin - a chemical byproduct - settles out. Considering the production capacities of modern biodiesel plants worldwide, this batch process requires a substantial investment for reactor batches and separator tanks.
On the website, a flow-chart shows how ultrasonication - this is the application of powerful ultrasound to liquids - can change the production process. Ultrasonication improves the mixing and increases the chemical reactivity of the reactants. This reduces the time needed for the chemical conversion by up to 90% leading to a whole new perspective on biodiesel making. Instead of pumping from batch to batch, the reactants are mixed continuously and subsequently pumped through a reactor column. A residence time of approx. 1 hour is sufficient for the conversion to complete. A centrifuge separates the glycerin from the biodiesel. Done! After washing and drying of the biodiesel, it is ready to be used.
Other benefits include a more complete transesterification of the tri- glyceride molecules, meaning that more oil is actually converted into biodiesel. Also, it requires less alcohol and catalyst - reducing production costs and improving the environmental effect.
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