Biodiesel Production

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Biodiesel Production

• John Nowatzki
• NDSU Extension Service

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Introduction

• What is Biodiesel?
• What is Transesterification?
• Biodiesel Production Process
• Biodiesel Engine Fuel Characteristics
• Biodiesel Strengths Weaknesses

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What is Biodiesel?

• Biodiesel is an engine fuel made from vegetable
  oils and animal fats
• The most common process used to convert these
  oils to biodiesel is called transesterification

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What is Transesterification?

• The reaction of an alcohol with the oil to form
  esters (biodiesel) and glycerol
• The reaction requires
• Catalyst (potassium or sodium hydroxide)
• Agitation
• An excess amount of alcohol
• The alcohol actually reacts with the fatty acids
  in the oil to form the mono-alkyl ester
  (biodiesel) and crude glycerol

Transesterification
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Results of Transesterification?

• The transesterification reaction results in the
  separation of the ester (biodiesel) and glycerol
  layers
• The heavier glycerol settles to the bottom and is
  removed
• 100 gallons of vegetable oil yields
• 99 gallons of Biodiesel
• 22 gallons Glycerol

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Biodiesel Production Process
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Biodiesel Production Process

• Mixing of methanol, catalyst and oil
• Sodium or potassium hydroxide is dissolved in the
  alcohol using agitation
• The alcohol/catalyst is added to the oil
• Temperature 100 -160 F for 1 to 8 hours
• Excess alcohol is used to ensure total conversion
  of oil to esters

Methanol
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Biodiesel Production Process

• Separation
• Glycerin is more dense than biodiesel
• Gravity separation makes it possible to draw
  glycerin off the bottom of the settling vessel

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Biodiesel Production Process

• Methanol Removal
• Excess methanol is removed from both the glycerin
  and biodiesel
• Evaporation or distillation
• The recovered methanol is re-used

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Biodiesel Production Process

• Glycerin Neutralization
• The glycerin contains unused catalyst and soaps
  that are neutralized with an acid to form crude
  glycerin.
• Salt formed during processing can be used as
  fertilizer.
• Water and alcohol are removed to produce 80-88
  pure crude glycerin
• Glycerin can be distilled to 99 purity and used
  in cosmetics and pharmaceuticals

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Biodiesel Production Process

• Biodiesel Wash
• The biodiesel is sometimes purified by washing
  with warm water to remove residual catalyst
• Resulting product is a clear amber-yellow liquid
  with a viscosity similar to petrodiesel.

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Biodiesel Production Process

• Biodiesel Quality
• Important quality control aspects of biodiesel
  production are
• Complete Reaction
• Removal of Glycerin
• Removal of Catalyst
• Removal of Methanol
• Absence of Free Fatty Acids

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Biodiesel Fuel Characteristics
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Biodiesel Strengths Weaknesses

• Potential Strengths
• Requires little or no engine modifications
• Easily blended with other diesel fuels
• Better lubricant than petrodiesel
• Production yields valuable byproducts
• Lower sulfate and hydrocarbon emissions than
  petrodiesel
• Current US Government subsidy
• Potential Weaknesses
• Gel problems at cold temperatures
• Fewer BTUs per gallon than petrodiesel
• Fuel filter plugging at lower temperatures
• Deterioration of seals in pre-1993 engines
• when using B10 or higher

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More Information

• http//www.ag.ndsu.nodak.edu/abeng
• John Nowatzki, NDSU Extension State Specialist
• Telephone [phone]
• Email John.Nowatzki_at_ndsu.edu