1. BIODIESEL
DR. ANU P. ABHIMANNUE
ASSISTANT PROFESSOR
DEPARTMENT OF BIOTECHNOLOGY
ST. MARY’S COLLEGE, THRISSUR.

2. Biodiesel
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur.
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 “Biodiesel is a renewable, biodegradable fuel that is
manufactured from vegetable oils and animal fats.”
 Produced by chemically reacting a vegetable oil or
animal fat with an alcohol such as methanol or
ethanol.
 In words, the reaction is: Oil + alcohol → biodiesel +
glycerin
 It is an alternative clean-burning renewable fuel
similar to conventional diesel.

3. Biodiesel
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur.
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 Due to its biodegradable nature, it is used as a
replacement for fossil diesel fuel.
 It can also be mixed with petroleum diesel
fuel in any proportion.

4. Important features
 Below are certain features of the fuel like:
 1) Biodegradable and Renewable Fuel.
 2) Safer to use and has low toxicity
 3) Lower exhaust emission rate than normal diesel fuel. It is a carbon-neutral liquid, which
means that combustion of biodiesel never produces the net output of carbon in the form of
carbon dioxide like other mineral diesel.
 4) Using biodiesel doesn’t require any diesel engine modification.
 5) Used as heating oil – In many commercial & domestic boilers, biodiesel is also used as
heating fuel.
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 4

5. Biodiesel Production
 There are three stages of this transformation of oil and fats to biodiesel.
 a) Base-catalyzed transesterification of the oil.
 b) The direct acid-catalyzed transesterification
 c) Finally conversion of oil to fatty acid and then the formation of biodiesel.
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur.
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6. Biodiesel Production
 Transesterification is the chemical process, which converts natural fats and
oils into Fatty Acid Methyl Esters (FAME) or Biodiesel.
 Some of the major sources of suitable oil (to make biodiesel) come from crops
like palm, soybean or rapeseed.
 High-quality biodiesel is made from rapeseed but nowadays most of the
biodiesel is produced from waste vegetable oils obtained from chips shops,
restaurants, and industrial food producers.
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 6

7. Transesterification
 The transesterification process is a reversible reaction and carried out by
mixing the reactants – fatty acids, alcohol and catalyst.
 A strong base or a strong acid can be used as a catalyst. At the industrial
scale, mostly sodium or potassium methanolate is used.
 The end products of the transesterification process are raw biodiesel and raw
glycerol.
 In a further process these raw products undergo a cleaning step.
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 7

8. Reaction
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 8

9. Substrate
 Soybean Oil
 Canola Oil
 Beef Tallow
 Pork Lard
 Exotic Oils As Walnut Oil Or Avocado Oil
 Even Used Cooking Oil Or Waste Oil
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 9

10. Disadvantages of biodiesel
At present, biodiesel fuel is more expensive than petroleum diesel fuel.
 Biofuels are a solvent and therefore can harm rubber hoses in some engines.
 As a solvent, biodiesel cleans dirt from engines. This dirt can then get
collected in fuel filters, clogging them. As a result, filters have to be changed
after the first several hours of biodiesel use.
 Biodiesel fuel distribution infrastructure needs improvement to make
biodiesel more widely available.
 In cold weather, pure biodiesel can thicken or gel, making it hard to pump
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 10

11. REFERENCES
 https://byjus.com/biology/biodiesel/
 https://ask.extension.org/questions/119003
Dr. Anu P. Abhimannue, St. Mary's College, Thrissur. 11