Biodiesel: a homegrown fuel solution

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Biodiesela homegrown fuel solution

• By Peter Meredith

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Outline

• What is biodiesel?
• What are its uses?
• How is it made?
• Pros and cons.
• Environmental impact

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What is Biodiesel?

• Biodiesel is a cleaner alternative to
  petrodiesel.
• It is a processed fuel made from biological
  sources.
• Biodiesel is renewable.
• Biodiesel is a mixture of alkyl esters of fatty
  acids .

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What are its uses?

• Biodiesel can be used in any diesel engine.
• Biodiesel can also be used as a heating fuel in
  domestic and commercial boilers.

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Production

• Biodiesel can be made from triglycerides which
  are available in many different forms such as
• Virgin oils (canola, soybean)
• Waste vegetable oils (WVO)
• Animal fats (lard, tallow)

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ProductionWhat is a triglyceride?

• Vegetable oils are triglyceride esters of fatty
  acids with chain length generally from 12-24
  carbons.
• They are made from glycerol and free fatty
  acids
• The R groups in the picture represent fatty acid
  chains, possibly of different lengths.

a free fatty acid
Glycerol
a triglyceride
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Production

• The production of biodiesel generally starts with
  one of three different techniques
• Base catalyzed transesterification of
  triglyceride with alcohol
• Direct acid catalyzed esterification of the
  triglyceride with methanol
• Conversion of the triglyceride to fatty acids,
  and then to alkyl esters with acid catalyst
• A base catalyzed transesterification of the oil
  with an alcohol is the preferred method as it
  produces higher yields at lower temperatures.

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Production

• The base catalyzed production of biodiesel
  usually follows these steps
• Catalyst-alcohol mixing
• Purification (when using WVO)
• Reaction
• Separation
• Removal of alcohol
• Wash

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Production Catalyst-alcohol mixing

• At this step the catalyst (NaOH or KOH) is
  dissolved in the alcohol (methanol). This is
  then thoroughly mixed.

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ProductionPurification

• The purification step is used when WVO is used.
  This is to clean the WVO of dirt, food remains,
  and anything else that should not be in the oil.
• Water and free fatty acids are also removed from
  the oil.
• The water is dried with a drying agent like
  magnesium sulfate. The free fatty acids are
  neutralized with base.

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ProductionReaction

• The oil of choice is now added into a reaction
  vessel with the catalyst/alcohol (NaOH/CH3OH)
  mix. This mixture is kept at a temperature just
  above the boiling point of methanol (337.8 K).
• This reaction then takes place

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3
Methanol
Triglyceride
BIODIESEL Glycerin
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ProductionSeparation

• After the completion of the reaction we will have
  a methyl ester (the biodiesel) phase and a
  glycerin phase.
• The glycerin phase is much more dense than the
  biodiesel phase so it can be removed by gravity
  filtration or by centrifuge.
• Both phases will have methanol still in them.
  This excess should be extracted from each phase
  by distillation.

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ProductionWash

• The biodiesel is then sometimes washed with warm
  water to clean the alkyl esters of any possible
  catalysts that remain or soaps that were
  produced.
• The biodiesel is then dried, and stored until it
  is put to use.

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Pros and Cons of Biodiesel

• Pros
• Carbon Neutral
• Non-toxic
• Can be neat or can be a mixture
• Higher flashpoint than petrodiesel
• Can prolong engine life
• Burns more efficiently than petrodiesel
• RENEWABLE

• Cons
• It is currently more expensive than petrodiesel
• Can deteriorate tubes and hoses in older model
  vehicles
• May cause filter blockage in low temperatures

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Environmental Impact

• Biodiesel biodegrades about 4 times faster than
  petroleum diesel.
• Emissions (for B100)
• Hydrocarbons average 67 reduction from
  petrodiesel
• Carbon monoxide average 48 reduction from
  petrodiesel
• Sulfur emissions are pretty much eliminated
• However, nitrogen oxide production is increased
  by 10-25. This can be lowered by catalytic
  converters.
• In the US, biodiesel is the only alternative fuel
  to have successfully completed the Health Effects
  Testing requirements (Tier I and Tier II) of the
  Clean Air Act.
• The exhaust from B100 can smell like a barbeque!

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Conclusion

• Biodiesel is a safe and environmentally friendly
  alternative to regular diesel.
• Biodiesel is synthesized by a simple chemical
  process. So simple that anyone can produce it in
  their own homes.
• Overall biodiesel shows some amazing potential to
  be a leading fuel source in the next couple of
  years.
• AND it is the only fuel that is fully endorsed by
  Willie Nelson. So much so that he actually has
  his own biodiesel company.

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Questions?
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References

• http//www.biofuelsystems.com/information.htm
• http//www.chemsoc.org/networks/LearnNet/green/bio
  diesel/home.htm
• www.biodiesel.org
• http//en.wikipedia.org/wiki/Biodiesel
• http//en.wikipedia.org/wiki/Biodiesel_production