What is Bio Diesel

Bio Diesel is a methyl or ethyl ester of fatty acid made from virgin or used vegetable oils (both edible and non edible) and animal fats. These oils can be transferred into Bio diesel by a special chemical reaction called Trans Esterification. In this process raw oil that contains triglycerides are converted into methyl ester, which helps to lower the oil’s viscosity and eliminates the risk of carbon deposits. Free glycerin is separated out from the oils as byproduct and purified methyl ester is obtained separately. This methyl ester is similar to some extent to Petroleum Diesel and can be used as 100% diesel substitute. Therefore, it is called Bio Diesel.

Just like petroleum diesel, bio diesel operates in compression ignition engines like Diesel Engines and hence does not require separate infrastructure. Bio-Diesel is considered clean fuel since it has no sulfur, no aromatics and has about 10% built in oxygen, which helps it to burn fully. Its higher cetane number improves the ignition quality even when blended in the petroleum diesel.

The main commodity sources of Bio-Diesel in India can be non-edible oils obtained from plants species such as Jatropha Curcas (Ratanjot), Pongamia Pinnata (Karanj), Calophyllum inphyllum (Neg Champa), Hevca Brasiliensis (Rubber) etc. Of these, some species have been evaluated and it has been found that Jatropha Curcas and Pngami Pinnata would be very suitable in our conditions. However, Jatropha Curcas has been found most suitable for the purpose.

Jatropha Curcas is a multipurpose drought resistant plant and belongs to Euphorbiaceae family. In English it is commonly known as purging nut or physic nut. Its growth is rapid and survives well in arid and semi arid tropics. It grows well in marginal/poor soil as well. It bears fruits for about 50 years and the seeds contain 35% to 40% oil and oil extraction can be 90-92%, which is more than other tree borne oil seeds. Jatropha plant is not eaten by animals or birds and does not require much fertilizer input. Raw Curcas oil can be mixed with diesel up to 20% and esterified oil is 100% diesel substitute which is cost-effective, renewable and environmentally safe. With volatility in the price of crude, the use of Bio Diesel is economically feasible as well.