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K-12 Chemistry Project :Laboratory preparation of Biodiesel

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Biodiesel : A higher calorific fuel choice


Bio-diesel is an environmentally green solution to the non renewable sources of energy that rule the energy crises of the planet. As part of a chemistry project for K-12 students we prepared bio-diesel in our laboratory. We studied the fuel efficiency of various vegetable oils and compared it to the biodiesel. Vegetable oils contain triglycerides that have similarities in structure to the petroleum derived diesel.

Preparation of Biodiesel: 100 cm3 of vegetable oil was measured in a 250 cm3 flask. To this 15 cm3 of methanol was added. This was followed by 1 cm3 of 50% KOH added drop-wise with constant stirring. The mixture was allowed to stand until the two layers separated out. The top layer is the impure bio-diesel. The lower layer is washed with H2O. Washing with water entails mixing the bio-diesel with water, allowing the bio-diesel and water to separate out after which the water layer is discarded. The clean bio-diesel is weighed .

Measuring the calorific values of different oils- In order to make a judicious comparison between the fuel efficiency of vegetable oils and bio-fuels. We determined the calorific values of different vegetable oils. The experiment was simple in tow with the humble facility of our chemistry laboratory. The spirit lamp with the vegetable oil was weighed before and after heating. The energy required to heat 50 g of water was calculated as q= m c delta T. 50 g of water was placed in a beaker. The initial temperature of the water in the beaker was noted. The water was heated till there was approximately a 50oC difference in temperature.

Conclusion:

. The fuel efficiency of the bio-diesel prepared from castor oil was determined to be 47 times more than the castor oil from which it was prepared. Cheaply available oils from both animal as well as from plants could be put to use as fuels by converting them into bio-diesels. Bio-diesel is a renewable energy made from waste or cheaply available fats. It causes lesser pollution. Bio-diesel can be easily used in currently existing fuel engines without any need for modification. It improves engine lubrication and increases the life of the engine since it is sulfur free. Fossil fuels on combustion release green house gases like CO2 in the atmosphere , however use of bio-diesel reduces the emission of fossil fuels in the atmosphere.

The experimental work of bio-diesel preparation was carried out at the R.N. Podar Sr Sec. School, Khar by Simant Shah and Pranat Siyal under the supervision of Ms. Anjali B. Gharpure