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Heat of combustion. 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 ...
The fuel value of coal varies in the same order. Some anthracite deposits contain pure carbon in the form of graphite . For bituminous coal, the elemental composition on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. [ 40 ]
Lignite is mined all around the world and is used almost exclusively as a fuel for steam-electric power generation. Lignite combustion produces less heat for the amount of carbon dioxide and sulfur released than other ranks of coal. As a result, lignite is the most harmful coal to human health. [3]
Gaseous fuels like methane have higher values than solid fuels like coal. Peat exhibits the lowest value of all common fuels. 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.
Energy density. In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. Often only the useful or extractable energy is measured. It is sometimes confused with stored energy per unit mass, which is called specific energy or gravimetric energy density .
The energy value of coal, or fuel content, is the amount of potential energy coal contains that can be converted into heat. [1] This value can be calculated and compared with different grades of coal and other combustible materials, which produce different amounts of heat according to their grade. While chemistry provides ways of calculating ...
Wobbe index. The Wobbe index (WI) or Wobbe number [1] is an indicator of the interchangeability of fuel gases such as natural gas, liquefied petroleum gas (LPG), and town gas and is frequently defined in the specifications of gas supply and transport utilities. If is the higher heating value, or higher calorific value, and is the specific ...
Food energy. Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity. [ 1] Most animals derive most of their energy from aerobic respiration, namely combining the carbohydrates, fats, and proteins with oxygen from air or dissolved in water. [ 2]