Bio-diesel consists of three principal feed stocks:
a) Oils or fats
Vegetable oil, animal fat, waste cooking oils, etc
b) Alcohol
c) Catalyst
The basic Reaction:
- Vegetable oil + methanol react to give biodiesel + glycerine
- A catalyst, temperature & mixing drive the reaction.
- Sodium hydroxide (NaOH, caustic soda or lye) is usually the catalyst. Potassium hydroxide (KOH, caustic potash) can also be used.
- Most of the reaction occurs in the first few mins. ~80% in 4min @ 55°C
(Ref Darnoko & Cheryan)
The Basic Bio-diesel Production Process:
The above schematic shows the basic chemistry involved in biodiesel production. Once the methyl ester has been formulated, the following production residues are still present:
Residual Methanol
Glycerol
Soap and metals
Residual catalyst: Sodium or Potassium
Moisture
Free Fatty Acids
All of these can have potentially harmful impact on engine performance and component wear.
Methyl esters are not classified as biodiesel until the proper specifications are met.
If you don’t clean and dry biodiesel what can happen?
- Corrosion of fuel injectors (water, catalyst)
- Elastomeric seal failures (methanol)
- Fuel injector blockages (glycerine, soaps etc)
- Increased degradation of engine oil
- Pump seizures due to high viscosity at low temperatures
- Corrosion of fuel tanks (excess water, catalyst)
- Bacterial growths and clogging of fuel lines/filters
Download the Biodiesel product catalogue
