list the common varieties of coal available. Show the order of each step during carbonisation
and give at least one important function of each variety of coal.
Answers
Answer:
Explanation:The ranks of coal (from most to least carbon content) are as follows: anthracite, bituminous coal, sub-bituminous coal, and lignite. The coal with the highest carbon content is the best and cleanest type of coal to use
Coal is classified into four main types, or ranks: anthracite, bituminous, subbituminous, and lignite. Anthracite: The highest rank of coal. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter.
Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite. Bituminous coal usually has a high heating (Btu) value and is used in electricity generation and steel making in the United States. Bituminous coal is blocky and appears shiny and smooth when you first see it, but look closer and you might see it has thin, alternating, shiny and dull layers.
Subbituminous: Subbituminous coal is black in color and is mainly dull (not shiny). Subbituminous coal has low-to-moderate heating values and is mainly used in electricity generation.
Lignite: Lignite coal, aka brown coal, is the lowest grade coal with the least concentration of carbon. Lignite has a low heating value and a high moisture content and is mainly used in electricity generation.
The precursor to coal is peat. Peat is a soft, organic material consisting of partly decayed plant and mineral matter. When peat is placed under high pressure and heat, it undergoes physical and chemical changes (coalification) to become coal.