Question

What are the different types of coal? What are their uses?

Answer 1

Hint: Coal is a combustible black or brownish-black sedimentary rock and mostly has carbon as its constituent along with other constituents being hydrogen, sulfur, oxygen and nitrogen.

Complete answer:
-Coal is a fossil fuel energy source that was formed millions of years ago and is primarily used as a fuel.
-The World Coal Association (WCA) explains the quality of coal is largely determined by:
(i) The type of vegetation the coal originated from;
(ii) The coal’s depth of burial;
(iii) Temperatures and pressures at that depth; and
(iv) How long it took the coal to form.
-The coal types can be arranged from lowest to the highest carbon content in four main types-
(i) Lignite- It is one of the low ranked coal and is the youngest form of coal. It is soft and ranged and its colour ranges from black to shades of brown, due to which it is sometimes called Brown coal. Lignite coal is mainly used to power generation and accounts for approximately $17%$ of the world’s coal reserves.
(ii) Sub-bituminous coal- After millions of years under continued pressure and temperature, lignite coal forms is converted into sub-bituminous coal. This coal form burns more cleanly than other types of coal due to its low sulfur content. This type of coal is also used in power generation and it accounts for approximately $30%$ of the world’s coal reserves.
(iii) Bituminous coal- This is one of the hard coal which is harder and blacker than lignite and subbituminous coal. Bituminous coal is divided into two parts: thermal and metallurgical which together makes up approximately $52%$ of the world’s coal reserves. Thermal coal is mostly used for power generation, cement manufacturing and other industrial purposes, whereas metallurgical coal is primarily used for manufacturing iron and steel.
(iv) Anthracite- This is also one of the hard coals and is the most mature coal. Anthracite is the coal form which has the highest carbon content. Anthracite is frequently used for home heating and accounts for about $1%$ of the world’s total coal reserves. Anthracite coal can be used as a smokeless fuel in domestic and industrial contexts.

Note:
China is the largest consumer and importer of coal. China mines produce almost half of the world’s coal followed by India with about a tenth. Australia is the third world exporter followed by Indonesia and Russia.