Biodiesel is a renewable, clean-burning diesel replacement that is creating jobs, improving fuel security and providing cleaner air for us to breathe.
Biodiesel is commonly made from vegetable oils such as canola oil, animal fats (tallow) or recycled greases such as used cooking oil. Other feedstocks being developed include algae, pomgania trees, jatropha, camelina and dry land juncea.
Biodiesel is made through a chemical process called transesterificaton. The process creates two products — methyl esters (the chemical name for biodiesel) and glycerin (a valuable byproduct usually sold to be used in soaps and other products).
The production of biodiesel, or alkyl esters, is well known and there are three basis routes to ester production from fats and oils
- Base catalysed transesterification with alcohol
- Direct acid catalysed esterification with methanol
- Conversion of oils to fatty acids and then to Alkyl esters via acid catalysis
The diagram below shows the general process for processing oils and fats that is reacted with methanol in the presence of a catalyst to produce glycerine and methyl esters (biodiesel).