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. To meet Wikipedias quality standards, this article or section may require cleanup. ... Coal (previously referred to as pitcoal or seacoal) is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). ... Heating value (or calorific value) is used to define the amount of heat released during the combustion of a fuel or food. ... A grade may refer to many different concepts, including: in various contexts: Each item in a (generally ordered and finite) collection of symbols or designators used as a particular grade system to distinguish and rank corresponding groups, where distinct members or instances of each group are regarded as sufficiently similar... Mass is a property of a physical object that quantifies the amount of matter and energy it contains. ...

Theoretical and real values

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). Chemistry (derived from alchemy) is the science of matter at or near the atomic scale. ... Heating value (or calorific value) is used to define the amount of heat released during the combustion of a fuel or food. ... In mathematics, theory is used informally to refer to a body of knowledge about mathematics. ... The chemical composition of a substance refers to the elements of which the substance is composed. ...

Purity

Coal consists primarily of carbon, but this is usually mixed with various impurities, including water and mineral matter such as sand and clay. The relative amounts of these impurities affects the usefulness of the coal as a fuel. The quality of coal can be determined by its rank and grade. Coal purity is ranked in an ascending order of carbon content: Lignite → sub-bituminous coal → bituminous coal → anthracite. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound. ... Water (from the Old English waeter; c. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... ... Coal Coal is a fossil fuel extracted from the ground by mining. ... Sub-bituminous coal is a coal whose properties range from those of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation. ... Bituminous coal Bituminous coal is a soft coal containing a tar-like substance called bitumen. ... Anthracite coal Anthracite (Greek Ανθρακίτης, literally a form of coal, from Anthrax [Άνθραξ], coal) is a hard, compact variety of mineral coal that has a high luster. ...

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. Moisture generally refers to the presence of water in trace amounts. ... Volatile is the name of more than one concept: A financial instrument with high volatility is considered volatile in economics. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Coal assay techniques are specific analytical methods designed to measure the particlar physical and chemical properties of coals. ...

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%: In physics, heat is defined as energy in transit. ... Combustion or burning is a complex sequence of chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. ... hello can you hear me For the card game, see Experiment (game). ...

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

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

See also

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