Alcohols

These include methanol (methyl alcohol), ethanol (ethyl alcohol), propanol (propyl alcohol), butanol (butyl alcohol) as compounds

-The OH group which replaces one of the H atoms in an alkane, gives these compounds their characteristic properties

-Specific heating value is lower than gasoline (42 – 43 MJ/kg)

methanol (19.7 MJ/kg) and ethanol (26.8 MJ/kg)

-For air-fuel mixture SHV is comperable with gasoline (MJ/kg-mixture at stoichiometric mixtures)

-Other alcohol groups such as dihydric and trihydric alcohols are not used as a fuel in IC engines

(i) Methanol

-Can be obtained from natural gas – has near and long-term potential

-Has high octane quality (130 RON, 95 MON)

-Can be used in low-concentration (5-15 %) in gasoline to increase octane number of the mixture

Problems;

-Poor solubility in gasoline, toxicity, low energy content (about half of gasoline), high latent heat of vaporization and oxygen content

-Contribute to poor driveability, incompatibility with some metals

-Produced from biomass

-It is made from the sugars found in grains, such as: Corn, Sorghum, and Barley

Other sources of sugars to produce ethanol include: Potato skins, Rice, Sugar cane, Sugar beets, Yard clippings, Bark, Switch grass etc.

-Has high octane number – can be used in low–concentrations in gasoline

-Most of the ethanol used in the United States today is distilled from corn

-Scientists are working on cheaper ways to make ethanol by using all parts of plants and trees rather than just the grain.

-About 99% of the ethanol produced in the United States is used to make "E10" or "gasohol," a mixture of 10% ethanol and 90% gasoline.

-Any gasoline powered engine can use E10, but only specially made vehicles can run on E85, a fuel that is 85% ethanol and 15% gasoline.

Alcohols: Methanol and Ethanol