Sunday, February 5, 2012

Vegetable Oil Diesel (Biodiesel)

Vegetable Oil Diesel (Biodiesel)

Vegetable oil, can be used directly or along with conventional diesel, kerosene or gasoline to run diesel engines. Chemically processing it can also help produce biodiesel. Know more about this alternative source of fuel...


Vegetable oil is an alternative source of fuel for running a diesel engine. Vegetable oil can be either converted into biodiesel by chemical processes, and be used as a fuel, or it can be directly used without any conversion. In the latter case, it is either straight vegetable oil (SVO) or pure plant oil (PPO) or waste vegetable oil (WVO) i.e. the oil discarded after cooking. For running a diesel engine, it can be used either alone or can be mixed with diesel or kerosene.


The history of using vegetable oil as a fuel, dates back to the 1900s, when the Otto company demonstrated the diesel engine designed to burn mineral oil at the World's Fair. Peanut oil was used as the fuel to run the engine. Then, extensive investigation was carried out by Rudolf Diesel to explore the potential of using vegetable oil as a fuel and predicted that in the course of time, its importance will increase and reach the level of natural mineral oils and petroleum products.


Another factor that triggered research on vegetable oil, was the occasional shortage of petroleum faced by the world in the 1930s, the 1940s and again in the 1980s. In the 1970s, the first commercial enterprise was formed to use straight vegetable oil in automobiles. Elsbett, a diesel engine, was invented by Ludwig Elsbett, and was specially designed to run on vegetable oil. However, the growing scientific interest in vegetable oil faced a setback with the falling petroleum prices in the 1980s and the increasing interest in biodiesel. Only recently, researchers have been able to find out the required fuel properties for using vegetable oil for running a diesel engine.


The main disadvantage of vegetable oil is that it has higher viscosity than biodiesel or petrodiesel, which is why it is not completely combusted. Incomplete combustion of vegetable oil leads to the deposition of carbon, which in turn can damage the engine. However, both the viscosity and the surface tension can be reduced by preheating the oil. The usual method is to install a heat exchanger and two fuel tanks, one for the diesel or biodiesel, and the other one for vegetable oil. In this way, the engine can be started up on diesel, which will ensure the preheating of the vegetable oil. Once the engine gets warmed up, it can be switched over to vegetable oil. Similarly, before turning off the engine, switching over to diesel is essential to make sure that no vegetable oil remains in the engine.


The main vegetable oil used in engines, include rapeseed oil or canola oil. However, some Pacific countries use coconut oil. Studies are also being conducted to explore the potential of using sunflower oil, especially in cold weather conditions. Pure vegetable oil is derived from plants. On the other hand, waste vegetable oil can be obtained mainly from restaurants. According to some estimates, the amount of excess waste vegetable oil produced mainly by the snack food factories, fast food restaurant and potato processing plants of USA was 11 billion liters. This huge amount of waste vegetable oil was supposed to be capable of offsetting almost 1% of the total oil consumption of United States.


The main advantage of vegetable oil is that it is cheaper and eco-friendly. In this age of global warming, and increasing fuel prices, it can emerge as an efficient alternative source of fuel. So, if adequate measures are taken for effective use as well as the dilution of the drawbacks, vegetable oil as an alternative fuel will reduce expenses and execessive dependence on fossil fuels.

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