Ultrasound accelerates the catalytic transesterification of vegetable oils and animal fats into biodiesel. This allows the change of the classical batch production to continuous production. Such a change reduces the investment costs and increased profitability.

Biodiesel is mainly produced in a batch process. Heat and mechanical agitation cause the process to energy and support the transesterification. The mixing by ultrasonic cavitation is an effective alternative for industrial transesterification of oils and fats into biodiesel.

Transesterification (Chemical conversion to biodiesel)

The production of biodiesel from vegetable oils, such as rapeseed oil or animal fat is through a catalytic transesterification of fatty acids with alcohol (methanol or ethanol) into the corresponding methyl or ethyl esters. Glycerin is a byproduct of this chemical reaction.

Vegetable oils and animal fats are esterified fatty acids. Three fatty acid chains linked to a glycerol molecule. In the transesterification of these three fatty acids are replaced by the action of a catalyst, such as potassium or sodium with methanol or ethanol. Three single fatty acid methyl ester molecules.

Triglycerides are esters, these esters are in turn to acids, for example, fatty acids, which are combined with alcohol. Glycerin (= glycerol) is a heavy alcohol. In the conversion process triglyceride esters are converted into alkyl esters (= biodiesel). Here, a catalyst and a Alkoholreagent, such as methanol, are used that yield methyl ester biodiesel. The methanol replacing the glycerol.

The glycerine - the heavier phase - falls to the ground. Biodiesel - the lighter phase - floats on top and can be separated, for example, with decanters or centrifuges. This conversion process is called transesterification.

The esterification reaction of the conventional batch process is relatively slow, and the separation of the glycerol phase is time consuming, often takes five hours or more.

The ultrasonic process

"We are very satisfied with the equipment and the service provided by Hielscher and plan to integrate the Hielscher ultrasonic technology in all our future investments."

Todd Stephens, Tulsa Biofuels

Source: www.hielscher.com