http://www.chemistryexplained.com/Ce-Co/Coal.html

Coal, a naturally occurring combustible solid, is one of the world's most important ... (The composition of a bituminous coal by percentage is roughly: carbon [C], ...

http://www.coaleducation.org/q&a/what_are_the_chemical.htm

Coal is not a homogenous substance meaning it has no fixed chemical formula. ... Coals other constituents include hydrogen, oxygen, nitrogen, ash, and sulfur.

https://en.wikipedia.org/wiki/Coal

Composition. Primary, carbon. Secondary. hydrogen · sulfur · oxygen · nitrogen · Lignite (brown coal). Anthracite (hard coal). Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called ..... In 2017 38% of the world's electricity came from coal, the same percentage as 30 years previously.

https://www.purdue.edu/discoverypark/energy/assets/pdfs/cctr/outreach/Basics8-CoalCharacteristics-Oct08.pdf

Indiana Center for Coal Technology Research. 1. Brian H. Bowen, Marty W. Irwin .... Macerals (microscopic organic constituents found in coal) are identified ...

https://www.ems.psu.edu/~radovic/Chapter7.pdf

constituents (minerals) and water (H2O). Most of the world's coal exists in the northern hemisphere. The United States, former. Soviet Union and China together ...

https://www.sciencedirect.com/topics/engineering/coal-composition

Why is coal composition and quality important to gas analysis? ..... The organic constituents of coal, including both the maceral groups (liptinite, inertinite, and ...

https://www.thebalance.com/all-types-of-coal-are-not-created-equal-1182543

Coals of varying composition are used as a combustible fossil fuel for ... estimates that global supply should increase at a rate of about 0.6 percent through 2020.

https://pubs.usgs.gov/pp/1625f/downloads/ChapterC.pdf

not necessarily harmful to the environment or human health but affect the use and efficiency of coal-burning equipment. For example, certain constituents in coal ...

https://geology.com/rocks/coal.shtml

As plant debris is exposed to the heat and pressure of burial, it changes in composition and properties. The "rank" of a coal is a measure of how much change ...

http://www.groundtruthtrekking.org/Issues/AlaskaCoal/TypesOfCoal.html

Apr 19, 2010 ... Anthracite: This is the highest ranked, hardest, oldest, and least common type of coal. It possesses a high energy content, high percentage of ...