Basis of coal

July.01 Coal

As received basis (ar): Analytic data calculated to the moisture condition of sample as it arrived at the laboratory and before any processing or conditioning . If sample has been maintained in a sealed state, so there has been no gain or loss, the as received basis is equivalent to the moisture basis as sampled .

Air dried basis (ad): A means of expressing an analytical result based on the condition in which a solid mineral fuel is in equilibrium with atmospheric humidity.

Dry basis (d): a means of expressing an analytical result based on the condition in which the solid mineral fuel is free from moisture

Dry ash free basis (daf): a means of expressing an analytical result based on a hypothetical condition in which the solid mineral fuel is considered to be free from both moisture and ash

Dry mineral matter-free basis (dmmf): a means of expressing an analytical result based on a hypothetical condition which the solid mineral fuel is considered to free from both moisture and mineral matter

Moist ash-free basis (maf): A means of expressing an analytical result based on a hypothetical condition in which the solid mineral fuel is considered to be ash-free but with a moisture content equal to the moisture-holing capacity.

Moist mineral-free basis (mmf): A means of expressing an analytical result based on a hypothetical condition in which the solid mineral fuel is considered to be mineral-matter-free but with a moisture content equal to the moisture-holding capacity

Moisture-holding capacity: The moisture content of a solid mineral fuel in equilibrium with an atmosphere of 96% relative humidity at a temperature of 30℃ determined under specified condition

Air drying : A process of partial drying of coal to bring its moisture near to equilibrium with the atmosphere in the room in which further reduction and division of the sample will take place.

Conversion

NOTE : Mar is Mt , all showed above can’t be used in net calorific value conversion