Biodiesel is produced from
vegetable oils, animal fats, various energy crops, seaweed, and a variety
of recycled oils. Biodiesel belongs to
the large family of renewable fuels and is the best known and widespread of biofuels.
Biodiesel is a natural and renewable alternative fuel for diesel engines, produced from vegetable oils, usually corn oil, soybean oil or sunflower oil. It contains no mineral oil and it is non-toxic and biodegradable. Burning biodiesel does not leave so many residues to the atmosphere, which leads to a significant reduction in pollutants that contribute to smog and global warming, emitting up to 85% fewer carcinogens. It is the only alternative fuel approved by the Environmental Protection Agency (EPA), has passed all Clean Air Act (CAA) health impact tests and meets the California Air Resources Board (CARB) requirements. Its normal use is as a diesel fuel, because its chemical composition is similar to that of diesel, that is, diesel fuel derived from the refining of crude oil.
Domestic biodiesel production has several advantages. It usually costs less than $0.50/lt, eliminates gas station visits and becomes a nice hobby. Biodiesel is prepared by simply heating vegetable oil together with methoxide (methanol + sodium hydroxide). Sodium hydroxide (NaOH) which is present in the methoxide dissolves the vegetable oil and allows molecules of methanol to be connected where glycerin molecules were connected before (methanol and glycerin are both alcohols). When the reaction is over, the dark colored glycerin is settled at the bottom while light biodiesel rises to the surface. At this stage of preparation the biodiesel layer is cloudy and this is because it still contains residuals of unbound NaOH and other impurities. Although some home-based producers use it in this form, most of them proceed to some additional processing steps in order to "wash" it from these impurities before using it.
Fully automated systems for converting vegetable oils and above all fried oils to biodiesel for use in any diesel machine (e.g. central heating boilers, diesel cars, trucks, tractors and agricultural machinery) are already available in the market. A typical domestic biodiesel production system is capable of converting 700 lt of oil into 700 lt of biodiesel within 2 hours and costs around $10,000.