Diesel fuel is a mixture of
hydrocarbons obtained by distillation of crude
oil. The important properties which are
used to characterize diesel fuel include cetane number (or cetane
index), fuel volatility, density, viscosity, cold behavior, and
sulfur content. Diesel fuel specifications differ
for various fuel grades and in different
countries. Diesel—whose first engine concept
was designed to use coal dust as the fuel—recognized that liquid
petroleum products might be better fuels than
coal. The engine was re-designed for
operation with liquid fuels, resulting in a successful prototype in
***5. Both the engine and the fuel still bear the name of
Diesel.
Diesel fuel is a mixture of
hydrocarbons—with boiling points in the range of **0 to **0°C—which
are obtained from petroleum. Petroleum crude oils are composed of
hydrocarbons of three major classes: (1) paraffinic, (2) naphthenic
(or cycloparaffinic), and (3) aromatic hydrocarbons. Unsaturated
hydrocarbons (olefins) rarely occur in the crude. It should be
noted that the terms paraffinic and naphthenic seem to be
obsolescent; we use them because they are still common in the
petrochemical industry. In modern chemistry, the respective groups
of hydrocarbons are called alkanes and
cycloalkanes.
