Subbitumiinihiili

Subbituminous coal is a type of coal that falls between lignite and bituminous coal in terms of its rank and properties. It is characterized by a lower carbon content and higher moisture content compared to bituminous coal, but it is more mature and has a higher energy content than lignite. The formation of subbituminous coal occurs under conditions of moderate pressure and temperature, resulting in a coal with a dull black or dark brown appearance.

The calorific value of subbituminous coal typically ranges from 10,000 to 13,000 British thermal units per pound (Btu/lb) on a moist, mineral-matter-free basis. Its sulfur content is generally lower than that of bituminous coal, which can be an advantage in terms of environmental emissions, although it still contributes to air pollution. Subbituminous coal is primarily used as a fuel for electricity generation in power plants. It is also used in some industrial processes, such as cement manufacturing. Its abundance and relatively lower mining costs make it an economically significant energy source in many regions.