“The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time.” - Rudolf Diesel in 1912.
Rudolf Diesel invented the Diesel engine. His first engine ran on vegetable oil on August 10 1893. Availability of cheap petroleum fuels overtook the use of vegetable oils. World remembers Rudolph Diesel on every August Ten as “ International Bio-Diesel day."
Global warming concerns today are making Diesel’s words come true. With depleting petroleum resources and CO2 emission concerns, the world is slowing turning towards bio-fuels, biodiesel will be an important alternative fuel source.
100 % Bio-Diesel or known as B100 from vegetable oil sources qualifies as renewable fuel and contributes to reducing the Carbon emissions. It has certain advantages over petroleum Diesel.
- This can blend in any proportion with petroleum Diesel.
- Biodiesel has better lubrication properties than petro diesel increasing the life of the engines.
- It has a higher centane number than diesel contributing to better efficiency and power.
- Low or nil sulphur dioxide emissions makes it more environmental friendly.
- Bo degradability also makes it more environmental friendly.
- Ordinary diesel engines can use this fuel without any modifications.
Tansesterifcation of a feedstock oil is the process by which biodiesel is made. The feedstock oil reacts with alcohol in the presence of a catalyst to separate the glycerols. The result is bio-diesel. The alcohol is recovered and reused. This makes the process cost effective.
Biodiesel Feedstock oil can be from a variety of sources:
Availability in large quantities is the primary concern. Since majority of the feedstock oils are from vegetable oils, diverting production to biodiesel produces a shift in the food chain cycle resulting in higher prices and scarcity. Higher food prices are not acceptable and can lead to great economic crisis.
Countries like India, which are nett importers of vegetable oil, cannot afford to spare agricultural land for biodiesel production. They have to produce bio-diesel from sources like Jatropha that can use marginal land not suited for agriculture.
Countries like Indonesia who are nett exporters can afford to use plantation crops like palm oil for bio-diesel production.
Quality of the feedstock should be suitable for simple and cost effective transesterification. Factors that affect the processing cost are :
- Consistency of the feedstock,
- lesser pre-treatment requirements ,
- lower amount of free fatty acids which have to be removed prior to transesterification,
- removal of elemental impurities like phosphorus.
Virgin vegetable oils are the main feedstock for bulk biodiesel production.Large areas under cultivation can produce large uantiites of feedstock oils. Bulk production is limited to few feedstock oils. They are :
- Soya bean oil accounts for the majority of biodiesel production in the United States.
- European Bio-diesel is mainly from Rapeseed oil.
- Palm oil, which has the highest yield, is in use in Indonesia, Malaysia.
- Jatropha oil is in use in India and Africa.
- China is trying out Pistacia Chinensis Bunge.
Other oils like used cooking oils , animal fats and host of other vegetable oil sources are being used in small scale or are under development for bio-diesel production.
Large areas are required for production of feedstock oils if it has to offset petro diesel. It should not affect the normal food supply chain. Using the vast expanse of the sea is the only alternative. Algae for biodiesel is becoming a promising alternative.