Biofuel Production from Algae

Biofuel from Algae

• Algae are targeted by biofuel manufacturers due to their high oil content.
• Extracted oil from algae is known as "green crude," which requires further processing to be usable as fuel.

Trans-Esterification Process

• Trans-esterification is essential for converting green crude into biodiesel.
• This process involves adding alcohol and a chemical catalyst to the crude oil.
• A chemical reaction occurs, forming a blend of biodiesel and glycerol.

Final Processing Steps

• The processing culminates by separating glycerol from the biodiesel mixture.
• The end result is biodiesel that is ready for use as a renewable fuel source.

Algal Deposits in Scotland

• A deposit rich in immature algae from the Central Valley of Scotland has potential for biofuel production.
• The extraction method includes retorting Torbanite, an oil shale also known as Boghead Coal.
• Retorting mobilizes organic matter, yielding an oil-like extract.

Analysis of Extracts

• The oil-like extract has been evaluated using gas chromatography techniques.
• The resultant gas chromatogram indicates characteristics similar to those of mature, relatively light crude oil.

Composition of Oils

• Oils consist of hydrocarbons, non-hydrocarbons that resemble hydrocarbons, and metals.
• Petroleum and its products are complex mixtures with thousands of compounds.

Oil Fractions

• Four primary fractions identified in oils:
  • Aliphatics (paraffin-naphthenes)
  • Aromatics
  • Nitrogen–Oxygen–Sulfur (NSO) compounds
  • Asphaltenes
• Asphaltenes are insoluble in solvents and resistant to biodegradation.

Hydrocarbon Types

• Aliphatic hydrocarbons include:
  • Normal alkanes (n-alkanes)
  • Branched alkanes (isoalkanes)
  • Cyclic alkanes (naphthenes)
• Isoalkanes, naphthenes, and aromatics have lower biodegradability compared to n-alkanes.

Hydrocarbon Saturation

• Saturated hydrocarbons are primarily composed of single carbon-carbon bonds, making them stable and unreactive.
• General formula for alkanes: CnH2n+2, where n is the number of carbon atoms.
• Condensed structural formula examples:
  • Butane: CH3CH2CH2CH3 or CH3(CH2)2CH3.

Isoprenoids

• Isoprenoids are branched saturated hydrocarbons used to infer depositional environments.
• Key isoprenoid compounds:
  • Pristane (Pr)
  • Phytane (Ph)
• Both compounds derive from the common precursor Phytol, with Pristane forming in oxidizing environments and Phytane in reducing environments.