Energy value of coal

Energy value of coal

The energy value of coal, or the fuel content, is the amount of potential energy in coal that can be converted into actual heating ability. The value can be calculated and compared with different grades of coal or even other materials. Materials of different grades will produce differing amounts of heat for a given mass.

While chemistry provides methods of calculating the heating value of a certain amount of a substance, there is a difference between this theoretical value and its application to real coal. The grade of a sample of coal does not precisely define its chemical composition, so calculating the actual usefulness of coal as a fuel requires determining its proximate and ultimate analysis (see "Chemical Composition" below).

Chemical composition

Chemical composition of the coal is defined in terms of its proximate and ultimate (elemental) analyses. The parameters of proximate analysis are moisture, volatile matter, ash, and fixed carbon. Elemental or ultimate analysis encompasses the quantitative determination of carbon, hydrogen, nitrogen, sulfur and oxygen within the coal. Additionally, specific physical and mechanical properties of coal and particular carbonization properties are also determined.

The calorific value ""Q"" of coal is the heat liberated by its complete combustion with oxygen. "Q" is a complex function of the elemental composition of the coal. "Q" can be determined experimentally using calorimeters. Dulong suggests the following approximate formula for "Q" when the oxygen content is less than 10%:

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

where "C" is the mass percent of carbon, "H" is the mass percent of hydrogen, "O" is the mass percent of oxygen, and "S" is the mass percent of sulfur in the coal. With these constants, "Q" is given in kilojoules per kilogram.

ee also

* Coal assay techniques
* Energies per unit mass
* Heating value


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Coal — Sedimentary Rock Anthracite coal Composition Primary carbon Secondary hydrogen, sulfur …   Wikipedia

  • Coal upgrading technology — refers to a class of technologies developed to remove moisture and certain pollutants from low rank coals such as sub Bituminous coal and lignite (brown coal) and raise their calorific values. Companies located in Australia, Germany and the… …   Wikipedia

  • Coal analysis —   Determines the composition and properties of coal so it can be ranked and used most effectively.   • Proximate analysis, determines, on an as received basis, the moisture content, volatile matter (gases released when coal is heated), fixed… …   Energy terms

  • Coal in Europe — describes coal as energy fuel in Europe today. Article focuses the role of coal in the energy in Europe in the near history and excludes the industrial revolution history. Coal includes hard coal, lignine, brown coal and peat …   Wikipedia

  • Coal analyzer — Coal analyzers are used by coal producers, coal preparation plants and coal fired power plants to determine coal quality in real time. Coal quality parameters of greatest interest include ash, moisture, sulfur, and energy value (also known as… …   Wikipedia

  • Coal grade —   This classification refers to coal quality and use.   • Briquettes are made from compressed coal dust, with or without a binding agent such as asphalt.   • Cleaned coal or prepared coal has been processed to reduce the amount of impurities… …   Energy terms

  • Coal sampling —   The collection and proper storage and handling of a relatively small quantity of coal for laboratory analysis. Sampling may be done for a wide range of purposes, such as: coal resource exploration and assessment, characterization of their… …   Energy terms

  • f.o.b. value — (coal)   Free on board value. This is the value of coal at the coal mine or of coke and breeze at the coke plant without any insurance or freight transportation charges added.   U.S. Dept. of Energy, Energy Information Administration s Energy… …   Energy terms

  • Coal Classification —   In the United States, coals are classified by rank progressively from lignite (least carbonaceous) to anthracite (most carbonaceous) based on the proximate analyses of various properties (fixed carbon, volatile matter, heating value, and… …   Energy terms

  • Coal rank —   The classification of coals according to their degree of progressive alteration from lignite to anthracite. In the United States, the standard ranks of coal include lignite, subbituminous coal, bituminous coal, and anthracite and are based on… …   Energy terms

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”