Heat value of coal:

Heat value of coal:

The heat value of or the energy value is the amount of energy that can be converted into the actual heating ability of the coal sample. The heat value is very important factor for any fuel, goes for conversion of energy or actual usefulness. By heat value the quality of coal or any fuel measured.

The basic parameters of coal sample analysis are moisture, volatile matter, ash, and fixed carbon. Moisture, ash, or volatile matter do not participate and creation of energy when coal is burnt; so the heat value is more depending on the fixed carbon a sample has. To be precise, heat value or heat of combustion is the energy released as heat when a compound undergoes complete combustion with oxygen. The chemical reaction is typically a hydrocarbon reacting with oxygen to form carbon dioxide (CO2), water (H2O) and since the reaction is exothermic, heat is generated. The quantity of heat generated is expressed as calorific value (Q), which is the heat liberated by its complete combustion with oxygen. It is expressed in terms of kcal/kg or Btu/lb (in British unit).

Generally, formula applies for calculation of calorific value Q is

Q = 337C + 1442(H - O/8) + 93S

Where, Q is the calorific value.

C is the fixed carbon content in the sample.

H is the hydrogen content.

O is the oxygen content.

S is the sulfur content in the sample.

Therefore, the quality of coal, in other words, the heat value of coal can be improved by reduction of ash content in coal sample. Coal beneficiation or washing of coal can reduce ash in coal.