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Additionally, specific physical and mechanical properties of coal and particular carbonization properties The calorific value Q of coal [kJ/kg] is the heat liberated by its complete combustion with oxygen. Q is a complex function of the elemental composition of the coal [citation needed]. Q can be determined experimentally using calorimeters.
The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions.
Table of specific heat capacities at 25 °C (298 K) unless otherwise noted. [citation needed] Notable minima and maxima are shown in maroon. Substance Phase Isobaric mass heat capacity c P J⋅g −1 ⋅K −1 Molar heat capacity, C P,m and C V,m J⋅mol −1 ⋅K −1 Isobaric volumetric heat capacity C P,v J⋅cm −3 ⋅K −1 Isochoric ...
The rank of coal is correlated with its geologic history, as described in Hilt's law. In the ASTM system, any coal with more than 69% fixed carbon is classified by its content of carbon and volatiles. Coal with less than 69% fixed carbon is classified by its heating value. Volatiles and carbon are on a dry mineral free base; heating value is ...
Thus methane has an HHV (Higher heating value) of 55.50 MJ/kg, the highest value of common fuels. Diesel fuel has an HHV value of 44.80 MJ/kg and anthracite coal a value of 32.50 MJ/kg. Moisture and ash-free firewood has a lower value of 21.70 MJ/kg while dry peat has the lowest value of all common fuels of about 15.00 MJ/kg.
All values refer to 25 °C and to the thermodynamically stable standard state at that temperature unless noted. Values from CRC refer to "100 kPa (1 bar or 0.987 standard atmospheres)". Lange indirectly defines the values to be standard atmosphere of "1 atm (101325 Pa)", although citing the same NBS and JANAF sources among others.
The Coldry Process is applied to brown coal with a typical moisture content of 60 per cent by weight and transforms the coal into a densified coal product of equal or better calorific value (5,800 kcal/kg) to typical export quality black coal, with less ash and sulfur content. Black coal equivalent derived from brown coal is ostensibly a ...
Coal or coke oven gas typically had a calorific value between 10 and 20 megajoules per cubic metre (270 and 540 Btu/cu ft); with values around 20 MJ/m 3 (540 Btu/cu ft) being typical. The advent of electric lighting forced utilities to search for other markets for manufactured gas.