There are a number of ways to reduce vegetable oil's viscosity. These methods include; transestrification, pyrolysis (Pyrolysis Definition from AFR), micro Emulsion (Emulsions & Emulsification – from Wikipedia), blending and thermal depolymerization. One of the most common methods used to reduce oil viscosity in the Biodiesel industry is called transesterification. It involves chemical conversion of the oil into its corresponding fatty ester.
Other methods of producing Bio-diesel from Algae Oil, other than transesterification, that have been considered to reduce the high viscosity of vegetable oil or algae oil are:
- Dilution of 25 parts of plant / algae oil with 75 parts of diesel fuel
- Micro emulsions with short chain alcohols (e.g. Ethanol or Methanol)
- Thermal decomposition, which produces alkanes, alkenes, carboxylic acids acids and aromatic compounds
- Catalytic cracking, which produces alkanes, cycloalkanes and alkybenzenes
However, when compared with the above, the Transesterification process appears to be the best choise, as the physical characteristics of fatty acid esters (bio diesel) are very close to those of diesel fuel, and the process is relative simple. Furthermore, the methyl or ethyl esters of fatty acids can be burned directly in unmodified diesel engines, with very low deposit.