Biofuel

Biodiesel

The term biodiesel refers to long-chain fatty acid alkyl esters made from vegetable oils, recycled cooking oils, or animal fats. It is most commonly produced by chemically altering an organic oil with methanol, by the use of a catalyst through a process called esterification. In the esterification process, the glycerine portion of the oil molecules is replaced by alcohol and is eventually removed from the mixture in the washing and drying process. Biodiesel is then formed.

(Source for above: This link will open in a new windowThis web page has hyperlinks which may transfer you to third-party website.http://www1.eere.energy.gov/biomass/pdfs/renewable_fuel.pdf)

Simplified Biodiesel Reaction (the no. in the original formula represent no. of units of ingredients and products)

Oil or Fat + Alcohol ----(catalyst)---> Glycerin + Biodiesel

The feedstock for biodiesel production is mainly vegetable oil, i.e. oil of rapeseed, sunflower or soybeans. To produce biodiesel, vegetable oil is firstly extracted from the oil-bearing seeds and then goes through the esterification process. Used oil, such as cooking oil and fat can be another source of biodiesel. However, when such kind of oil is used, purification treatment is needed before the esterification process. Nowadays, rapeseed is the principal feedstock for biodiesel production in the European Union, soybeans are mainly used in the USA, and the use of sunflower and palm oil is mainly found in warm/hot climate regions.