Ranking of Coal

Rank is an inherent property of the fuel, depending upon its relative progression in the classification process. The ranking of coal is based on the fixed carbon and heating value of the mineral matter free analysis. The ASME (American Society of Mechanical Engineers) and ASTM (American Society of Testing and Materials) have accepted the following ranking specifications for coal:

1. Higher ranking: It is done on the basis of heating value (moist basis).
2. Lower ranking: It is done on the basis of heating value (most basis).

For example, A coal ranked as 62–20,000 means that the coal contains C = 62% and C.V. = 20,000 kJ/kg.