Grading of Coal

The grading of coal is done on the following basis:

1. Size
2. Heating value
3. Ash content
4. Ash softening temperature
5. Sulphur content

For example, a coal grade written as 5–10 cm, 20,000 – A8-F24 – F1.6 indicates that the coal has

Size: 5–10 cm

C.V.: 20,000 kJ/kg

Ash: 8–10%

Ash softening temperature: 2400–2500°F

Sulphur content: 1.4–1.6%