CLASSIFICATION OF FUELS

Fuels may be classified as follows:

1. Based on their occurrence, they are classified as natural fuels and artificial (or prepared) fuels.Natural fuels occur in nature and they are also called primary fuels, whereas artificial fuels are prepared by further processing of primary fuels and they are also called secondary fuels.
2. Based on their state, they are classified as solid fuels, liquid fuels, and gaseous fuels.A detailed classification of fuels is given in Table 1.1.

Table 1.1 Classification of fuels