Biobutanol - the superior biofuel
Butanol is a 4-carbon alcohol originally central to a number of industrial chemical processes. It is now recognised as an important transport fuel - with superior characteristics to ethanol.
Butanol is produced by solventogenic clostridia via the Acetone-Butanol-Ethanol fermentation. The history of the ABE fermentation stretches back to the early 1900s and it was once only second to ethanol as the largest industrial fermentation. Its demise was ultimately triggered by the availability of cheaper alternatives from the petrochemical industry. The search for a sustainable biofuel has now established biobutanol as a important transportation fuel.
Butanol as a transport biofuel
Unlike conventional biofuels, such as ethanol and biodiesel that are mainly derived from food-based feedstocks, biobutanol is an advanced biofuel that can be derived from non-food sources and used as a stand alone transportation fuel or blended with petrol or diesel. Its inherent chemical properties make it superior to ethanol for use in combustion engines:
- With 4 carbons, butanol has more energy than ethanol - 25% more energy per unit volume.
- Butanol has a lower vapour pressure and higher flashpoint than ethanol, making it easier to store and safer to handle.
- Butanol is not hygroscopic while ethanol attracts water. Ethanol has to be blended with petrol shortly before use. Butanol can be blended at a refinery without requiring modifications in blending facilities, storage tanks or retail station pumps.
- Butanol can run in unmodified engines at any blend with petrol. Ethanol can only be blended up to 85% and requires engine modification.
- Unlike ethanol, butanol may also be blended with diesel and biodiesel.
- Butanol is less corrosive than ethanol and can be transported using existing infrastructures.