Cetane Number

Cetane Number:- Cetain number is used for grading the diesel oils. Two compounds have been selected as standard Hexadecane has been assigned cetane number 100 while alfa methyl naphthalene is assigned zero cetane number on the basis of ignition property.

The cetane number of a diesel oil is the percent of cetane by volume in a mixture of cetane and alpha methyl naphthalene which has the same ignition property as the fuel oil in question under similar experimental conditions. Thus, the diesel oil having cetane number 75 would have same ignition property as a mixture of 75% cetane and 25% alpha methlyl naphthalene.