Course: BFM 202 Biodiesel Production

Lecture

Alternative Technologies for Fatty Acid Ester Synthesis
Credits
BFM 202 Biodiesel Production Unit 4 Lecture has been adapted from "ENGY 131 Lesson 4 Alternate Biodiesel Feedstocks” by Southeastern Illinois College.

ENGY 131 Biodiesel Production course content by Southeastern Illinois College is licensed under a Creative Commons Attribution 3.0 Unported License. Except where indicated otherwise.

Alternative Technologies for Fatty Acid Ester Synthesis

Click on each of the alternative technologies below for more information:
Monophasic Transesterification

This method requires the use of an organic solvent to render the conversion to one phase. The advantages are that less catalyst is needed, reaction times are reduced from hours to minutes, the methyl ester yield is normally around 98%, and lower temperatures are needed for the reaction. Solvents used are: hexane, methyl tert-butyl ether, and tetrahydrofuran. Disadvantages are that the tetrahydrofuran and un-reacted methanol must be recovered and that these solvents are flammable and introduce hazard.

Microwave (enhanced) Transesterification

Microwave or radio frequency radiation has been used in alkali-catalyzed ester reactions and has proven to significantly increase reaction rates to where 90% of the reaction is completed in 3-8 minutes. The alcohol absorbs the energy thereby increasing the reaction rate.

Acid-catalyzed FAE Synthesis

Acid catalysis produces the biodiesel from grease with sulfuric acid used for the reaction. This method uses high reaction temperatures, five times more alcohol, long reaction times and costly production processes.

Direct “in situ” Transesterification of Substrate-resident Liquid

Using sulfuric acid “in situ” transesterification of whole sunflower seeds, hulls and all, with methanol provided a 20% yield increase over that realized with only the extracted oil. This is due to the process ability to utilize the lipids in the hulls. This method has successfully increased the yields with rice bran and ground soybeans as well.

Uncatalyzed Ester Production

The use of high temps and high pressures to convert the reaction but are expensive due to increased alcohol usage and higher capital costs.

Direct Fatty Acid Alykyl Ester Production via Pathway Engineering (microdiesel)

Genetic engineering of cellular metabolism to create fatty acid ethyl esters has resulted in a product referred to as” microdiesel.” This emergent technology has yet to be a viable production method.