bio-diesel is a bio-synthetic fuel that is similar in use to the mineral diesel fuel. In Europe, it is usually produced by transesterification of rapeseed oil with methanol. Therefore, the correct appellation of bio-diesel is in that case "rapeseed methyl ester", short RME. In other countries, bio-diesel will be obtained with other vegetable oils, which show slightly different properties.
Raw materials for the production of bio-diesel
The raw material for rapeseed oil, the rape plant, was cultivated on about 1,5 millions ha arable land by the sowing of 2009. The amount of hybrid breeds equals 65%. Genetically modified breeds are non relevant in Germany, therefore rapeseed-oil is a sustainable resource obtained in domestic production. Furthermore, bio-diesel is made out of renewable resources and preserves the reserves of fossil burnings.
The second raw material, methanol, is gained out of a synthetic gas, a mixture of carbon monoxide and hydrogen with a ratio of about 1:2.
Production of bio-diesel
The production of bio-diesel is quite easy at first sight. Methanol will be added a catalyzer (usually a base). It is then mixed with the rapeseed oil. The process of transesterification happens via constant stirring. A glycerin molecule in the oil molecule is then replaced with methanol. This generates two reaction products:
- bio-diesel/ rapeseed methyl ester
Both reaction products are separated from each other during further processes and cleaned of methanol rests. Next step is the distribution of the products.