What is Coal Used For

Coal is a fossil fuel, which has found a wide range of applications and uses in modern world. Coal was believed to form during the carboniferous age (285 to 345 million years ago), from the plant and organic matter that accumulated at the bottom of the water bodies. It is believed that during that period, much of the Earth was covered by swamps and lagoons, where many plant species grew and then died. The remains of the plant and other organic matter deposited at the bottom of such water bodies, and then slowly formed peat bogs. The peat bogs got compressed under the Earth's surface due to the accumulation of sediments over it. Over million of years, the compressed peat gradually metamorphosed into coal under the effects of extreme heat and pressure.

Types of Coal

Coal is a black or brown colored readily combustible sedimentary rock that is primarily composed of carbon. Coal can also contain small quantities of a few other elements like, oxygen, nitrogen, hydrogen and sulfur. Coal is basically classified into four types, known as lignite, sub bituminous, bituminous and anthracite coal. Lignite is the softest coal with high moisture content, while anthracite is the hardest coal with highest carbon content and lowest moisture and ash content. Sub bituminous coal is medium soft with a moisture content lower than lignite. On the other hand, bituminous coal contains very little moisture, and is harder than both lignite and sub bituminous coal. Out of these, bituminous and anthracite are two most important types of coal.

Uses of Coal and its By-products

In the recent times, coal is mainly used to generate electricity. It is a reliable and low cost energy source for the generating electricity. In the United States, about 50% of electricity is generated from coal. In addition to electricity generation, coal is used by many manufacturing plants and industries to make paper, chemicals, steel, metal products, plastics, ceramics, fertilizers and coal tar. It is used as a source of heat in the production of bricks and cement. Gases such as, coal gas, water gas and producer gas, which are obtained by burning coal are used to supplement natural gas.

Coal is also used for producing coke, which can be termed as another important use of this fossil fuel. Coke is primarily used in steel industry and as high carbon fuel for metal processing. It is mainly a coal residue, which is obtained by heating coal under controlled conditions, and in the absence of air. This helps to concentrate the carbon content of coal. Apart from coke, other coal derived compounds or residues are used in a wide range of manufacturing processes including, plastics, synthetic rubber and fiber, insecticides, paints, medicines and solvents. Coal is also employed by many for cooking and heating buildings.

Bituminous Coal
Bituminous is the most widely available coal and is ranked higher than lignite, but lower than anthracite coal according to quality. Bituminous coal is primarily used to generate electricity and produce coke, which is used in steel industry. The sub bituminous coal is also used to produce steam for electricity generation. Bituminous coal has higher heating value than both lignite and sub bituminous coal.

Anthracite Coal
Anthracite is the hard coal with the highest carbon content and lowest moisture content. It is considered as a good heating fuel. It is used for space heating along with electricity generation. Anthracite is of higher quality than bituminous and the other types of coal.

Coal Tar
Coal tar is a residue that is obtained during the distillation of coal. Coal tar is obtained as a thick and black colored liquid during the coal distillation process. It has a large number of applications, right from building and home repair to fabric production and treatment of certain conditions. More commonly, coal tar is used for insulating buildings, making buildings waterproof and for the production of fabric, paints, soaps and shampoos. The soaps and shampoos containing coal tar are used for conditions like, dandruff, skin sores and psoriasis.