Classification of Coal
Coal, a combustible black or brownish-black sedimentary rock that is composed of carbon and various other elements, is an important source of energy for human civilization. Over the years, coal has been classified into different types based on its physical and chemical properties. These types are also referred to as ranks and are used to differentiate the quality of coal. This article provides an overview of the major types of coal, their properties and applications.
Anthracite
Anthracite is the highest rank of coal and is classified as a metamorphic rock. It is black and very shiny due to its high carbon content, and it is the hardest and least permeable type of coal. Anthracite is known for its low sulfur content, low ignition temperature and high energy density. It is typically used for home heating, power generation, and in smelters for the production of steel.
Bituminous Coal
Bituminous coal is the second highest rank of coal and is typically black and brittle. It has a higher calorific value than lignite or sub-bituminous coal and contains more volatile matter, which makes it ideal for power generation. It is primarily used in power plants for the production of electricity, although it is also used for domestic heating and industrial applications.
Sub-bituminous Coal
Sub-bituminous coal is the third rank of coal and is softer than bituminous coal. It has a lower carbon content and higher moisture content than bituminous coal, but it still contains more energy than lignite. Sub-bituminous coal is used primarily for power generation and is also used in cement and aluminum production.
Lignite
Lignite is a type of soft coal that is brownish black in color. It is the lowest rank of coal, with the lowest energy content and the highest moisture content. It is typically used for power generation and is also used in the production of fertilizer.
Ganister
Ganister is a sedimentary rock that is composed of a cemented mixture of clay, sand and gravel. It is usually light brown and is often mistaken for coal due to its color and texture. It is used primarily in the production of refractory materials.
Conclusion
This article has provided an overview of the different types of coal and their physical and chemical properties. Coal is an important source of energy for human civilization and is used for a variety of applications. Different types of coal are used for different applications based on the particular properties of each type.
