Conventional diesel and fuels are products of petroleum. They are now in shortage and in high demand, hence the increased price we’ve been seeing at the pump over the past few years. This has caused every country to be on the look-out for cheaper and renewable resources of diesel. Conventional petroleum is a product of coal and other decaying plants in the earth in high pressure, and the formation of which takes years. However, biodiesel that is produced form plants is a renewable source.
Biodiesel seems to be the best substitute or optional fuel. It is produced from domestic resources, such as crops or plants that are high in oil content. Another added benefit is that the life of automobile engines is also increased as biodiesel is a good lubricating agent. It is also safer to handle than petrodiesel.
Biodiesel production sources vary from vegetable oils, plant oils, animal fats, greases etc. These are converted into fatty acid methyl esters (FAME). For its synthesis, 3 major steps are to be followed irrespective of the source:
1) Transesterification of the oil – Alkali mediated
2) Transesterification of oil – Acid mediated
3) Oil to fatty acid conversion and production of biodiesel.
Transesterification is the process of exchange of ester groups and alkoxy group catalyzed by an acid or base. Here, glycerin is separated from the vegetable oil leaving behind methyl esters, which is essentially biodiesel. The glycerin is a byproduct used in soap production.
Biodiesel lacks petroleum and can be used in pure, or blended to any level with a petroleum diesel to recreate a biodiesel blend. The blends are named B20 for those that contain 20% Biodiesel and 80% petrodiesel and B5 for containing 5% biodiesel and 95% petrodiesel. B100 is 100% pure biodiesel. The blends usually are prices about the same as petrodiesel, while the pure forms of B99 or B100 are generally priced at higher rates.
This blend can be used for combustion of diesel engines with minimum or no changes. Biodiesel is said to be ‘clean burning’ i.e. does not emit pollutants like Carbon mono oxide, sulphur (100% SO2 emission free) smoke, etc. Hence, it can be called an eco – friendly solution to the environmental pollution issues.
Biodiesel usage does not require the changes of internal engines or other body parts. Modifications are required only if the engine has rubber fuel lines. This change does not have any adverse effect on the performance or power of the engine. The gasoline engines are not compatible with biodiesel, making conventional compression-ignition (diesel) engines a requirement for anyone who wants to run their vehicle on biodiesel.
The blended forms of biodiesel are available at affordable rates. In 1998, a biodiesel study was jointly conducted and sponsored by the US Department of Energy and the US Department of Agriculture, reported net carbon dioxide emissions to be up to 78 percent lower when biodiesel was used compared to petroleum based diesel.
Surprisingly, biodiesel is not a boon only for cars. Itt can be used for trains, aircraft, and even as heating oil for domestic and commercial purposes. Heat produced from biodiesel is referred to as bioheat. Again, rubber piping should be changed as they will be affected by the solvent property of biodiesel.