As a result of geographical upheaval millions of years ago, the trees which were buried in the ground were converted into coal due to excessive heat and pressure. Thus coal is a fossil fuel. Coal is said to be the father of the industrial revolution because initially, coal used to be a major source of energy in factories yesterday. It is also called black gold due to the usefulness of coal. China is the largest consumer and importer of coal in the world. On the other hand, Australia is the world’s largest coal exporter.

Types of coal

Coal India Limited is the largest company in the public sector ie the cooperative sector to produce or mine coal. It is a Maharatna company. It was established in 1975. Most of the coal in India is of the non-coking category. This iron is considered to be of a good grade for use in the steel industry. Therefore, coking coal for the iron and steel industry is imported from China and Australia. Coal has a high carbon and a low amount of moisture, we call it coking coal.

Types of coal

Carbon is the major element of coal. The more it is found in coal, the more heat the coal generates. On the basis of the amount of carbon, coal is divided into the following four parts-

a) Anthracite coal:

This is the best coal which is very black, shiny, and airy. Normally up to 95% carbon is found in it. Carbon is 65 to 93 percent in Pennsylvania-Anthracite, 4 to 95 percent in South Wales Anthracite, 71 percent in Saxony Anthracite, and 99 percent in Anthracite from Southern Russia. Its hardness is from 0.5 to 2.5 and the relative density is from 1.34 to 1.4. It burns with difficulty, but once ignited, it keeps on burning till the end.

Types of coal

b) Bituminous coal:

Bituminous coal also called soft coal. It is black or dark brown. This coal is used to make steel from iron. It contains 70 to 85% carbon content. High-grade bituminous coal is used in metal refining. Its quality is superior to lignite but continuous to anthracite. This type of coal is used in steam and electric-powered locomotives. Coke is also manufactured from this coal.

                           Components and Heating Value of Coal by Rank
% Weight Anthracite Bituminous Sub-Bituminous Lignite
Heat Content (Btu/lb) 13000-15000 11000-15000 8500-13000 4000-8300
Moisture < 15% 2-15% 10-45% 30-60%
Fixed Carbon 85-98% 45-85% 35-45% 25-35%
Ash 10-20% 3-12% ≤ 10% 10-50%
Sulfur 0.6-0.8% 0.7-4.0% < 2% 0.4-1.0%

c) Peat coal:

It is raw coal and burns heavily in wood. This is the pre-construction stage of coal. The amount of carbon in it ranges from 30% to 55%. On burning it, more ash and smoke come out. This is the lowest grade of coal. In India, this coal is found most in Rajasthan and Jharkhand.

d) Lignite coal:

Lignite coal is also known as brown coal. It contains 60% to 70% carbon content. Lignite is stone coal of inferior class. Its color is brown or blackish-brown. It has a high amount of water vapor, so it produces more smoke at the time of burning and also leaves ashes. Its major reserves in India are found in Neyveli, Tamil Nadu. Two other areas of lignite coal in India are Makum in the state of Assam and Palna in the state of Rajasthan.

Uses of coal

Coal is easier and safer to transport, store and handle than the alternative, highly flammable fossil fuels. It is a major source of energy. 35 to 40% of the total energy used is derived from coal. Coal is mainly used as a fuel to make electricity. The heat generated by burning coal is used to convert water into steam, which drives the turbine. Other major uses of coal are as follows:Types of coal

  1. As a fuel in domestic works,
  2. As a means of power in industries,
  3. As a raw material,
  4. As steam power,
  5. In metal refining,
  6. Making iron from steel
  7. In cement industries
  8. In electricity generation
  9. In chemical production

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