Biodiesel vs Fuel

1. BIODIESEL
By Syuanne Lee

2. What is Biodiesel?
• Biodiesel is an alternative diesel fuel.
• It is made from renewable resources such as
vegetable oils and animal fats.
• Being made from renewable resources, it has a
carbon neutral footprint.
• Vegetable oil is too thick to flow through modern
diesel engines without causing damage, so we
can lower it’s viscosity through a process called
transesterification.

3. Differences in Structures
• A typical molecule of biodiesel looks like the
structure below. Mostly it is a long chain of
carbon atoms, with hydrogen atoms attached,
and at one end is what we call an ester
functional group (shown in blue).

4. • Diesel engines can burn biodiesel fuel with
no modifications (except for replacing some rubber tubing
that may soften with biodiesel). This is possible because
biodiesel is chemically very similar to regular diesel, shown
below. Notice that regular diesel also has the long chain
of carbon and hydrogen atoms, but doesn’t have the ester
group present in biodiesel.

5. • Vegetable oil also has the long rows of carbon and hydrogen
atoms, but is about three times larger than normal diesel
molecules. It also has ester function.
• That larger size of vegetable oil means that in cold weather it gels,
making it hard to use in an engine. Converting it into biodiesel
makes it a smaller molecule, closer to the size of regular diesel, so
that it has to get colder than vegetable oil before it starts to gel.

6. Transesterification
• Transesterification is the chemical process which
replaces one type of alcohol for another in an ester.
• An ester is made by combining an alcohol with an acid.

7. Chemical Conversion of
Vegetable Oil to Biodiesel
• Vegetable oil, like biodiesel, belongs to a category of compounds
called esters.
• This chemical reaction requires using methanol (shown in green),
which causes the red bonds in the structure below to break.
• This breaks off the blue section, like a backbone on the molecule,
which becomes glycerol.
• The red bonds that did go to the glycerol backbone are placed with
bonds to methoxy groups, shown in green in the final structure,
that came from the methanol

9. Additional Steps in Making
Biodiesel
• The first step is to remove any traces of water in the vegetable
oil. This is to prevent soap formation as shown below.
• If soap is made, it complicates the steps after the
transesterification reaction (separation of the biodiesel from
leftover methanol, the NaOH or KOH catalyst, and the glycerol
by-product).

10. Green Chemistry
• Less Hazardous Chemical Syntheses: Wherever practicable,
synthetic routes should be designed to use and make
substances that have little or no toxicity to human health and
the environment. Biodiesel is made from cooking oils and
alcohol, so if you spill it on the ground, it will quickly degrade
into natural organic residues. Biodiesel is as toxic as table salt,
and safe to handle. Mechanics who use biodiesel notice that
their hands don’t crack and dry out the way they do with
diesel fuel. Many people use biodiesel in marine environments
to protect wildlife and hatcheries.

11. • Use of Renewable Feedstock: A raw material (or feedstock)
should be renewable if technically and economically
practicable. Natural, renewable resources such as vegetable
oils and recycled restaurant greases can be chemically
transformed into clean-burning biodiesel fuels. As its name
implies, biodiesel is like diesel fuel except that it’s organically
produced. Biodiesel can be made from many oils and fats such
as soy, canola, tallow, mustard, and restaurant greases.

12. • Real-time Analysis for Pollution Prevention: Analytical
methods need to be improved so that monitoring of each step
can be performed during the manufacturing process to detect
and control formation of hazardous substances. There is no
use of sulfur in the making of biodiesel, so biodiesel won’t
contribute to sulfur dioxide emissions or poison exhaust
catalyst. This is unlike some diesel fuels which contain sulphur
but does not use it, hence releasing it as sulphur dioxide or
trioxide. The by product of biodiesel is also just glycerol, which
is not a hazardous substance. After production, the emission
of gases are also reduced as stated below.

13. Differences Between Carbon
Dioxide Emitted by Biodiesel
and Diesel

14. Myth
• Biodiesel releases less carbon dioxide
compared to diesel
• Amount of carbon dioxide released by
diesel and biodiesel are similar
Truth

15. Biodiesel
• Releases carbon dioxide
which plants extracted a
short period of time ago
• This is done by the natural
carbon cycle
• No net increase in the
percentage of carbon
dioxide in the atmosphere

16. Diesel
• Carbon dioxide emitted is actually those
which was sequestered from the
environment million years ago
• Result in a cumulative net increase of
carbon dioxide

17. Net Increase in Carbon Dioxide
causes
• Global warming (caused by greenhouse effect)
• Polar ice caps melt
• Ice caps are fresh water
• desalinate the ocean- make it less salty
• Species which cannot adapt (no evolution) will
extinct
• Disrupt the food chain- unbalanced ecosystem

18. Sulfur Dioxide from Diesel
causes
• Acid Rain acidifies the lake, stream and soil
• Corrosion of buildings and monuments
• Reduces visibility because of soot

19. Problems brought by Biodiesel
• Certain biodiesel gels easily under cold
temperature
• Deforestation for plantation
• Degrades rubber in old cars
• Synthetic rubbers that are resistant

20. Bibliography
Clean Air Trust. 1999. Sulphur Dioxide. Retrieved 3 September 2013,
from http://www.cleanairtrust.org/sulfurdioxide.html.
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September 2013, from http://auto.howstuffworks.com/fuel
efficiency/biofuels/10-disadvantages-of-biofuels.htm#page=7.
Gan, W.Y. 2008. SUCCESS: Biology SPM. Chapter 9: Endangered
Ecosystem. Oxford Fajar.
Goshen College. (n.d.). The Chemistry of Biodiesel: The Differences
between Biodiesel, Diesel and Vegetable Oil. Retrieved 3 September
2013, from http://www.goshen.edu/chemistry/biodiesel/chemistry-
of/.
Jaccard, M. 2006. Sustainable Fossil Fuels the Unusual Suspect in the
Quest for Clean and Enduring Energy.

21. Perritano, J. (n.d.). Top 10 Advantages of Biofuel. Retrieved 2
September 2013, from http://auto.howstuffworks.com/fuel-
efficiency/biofuels/10-advantages-of-biofuels.htm.
Schreurs, M. A. & Papadakis, E. 2009. The A to Z of the Green
Movement.
Shaine Tyson, K. National Renewable Energy Laboratory. 2000.
Biodiesel for the Global Environment: Biodiesel—the Clean, Green
Fuel for Diesel Engines. Retrieved 3 September 2013, from
http://www.biodieselgear.com/documentation/NBB_Biodiesel_brochu
re.pdf.
Simmons. (n.d.). 20 Deadliest Effects of Global Warming. Retrieved 3
September 2013, from
http://www.environmentalgraffiti.com/sciencetech/5-deadliest-
effects-of-global-warming/276?image=2.
Srinivas. 2011. Difference between diesel and biodiesel. Retrieved 2
September 2013, from http://www.knowitsdifference.com/difference-
between-diesel- and-biodiesel/.