Coal:Uses, Classification, Advantages and Disadvantages
What is Coal?
Coal is a fossil fuel, which is by definition a fuel that derives from fossils of plants or animals that died long ago. Some people also use the word ‘coal’ to refer to charred wood that has finished burning, or is smoldering.
Coal comes in the form of rock like lumps. It is used widely in furnaces both domestically and in factories to provide heat or to power machinery.
The word ‘coal’ comes from an Old English word, ‘col’. This word in its turn has Germanic roots. ‘Col’ meant a glowing ember in Old English. It was only until after the tenth century that ‘coal’ came to mean what it means today: a mineral that is burned and used as fuel.
Coal is a black or brown rock. It consists mainly of Carbon and is known as carbonaceous rock. It is formed by the compressed vegetative remains of past ages. Most coal deposits are of carboniferous age, i.e. about 300 million years old. More recent deposits of Tertiary age are usually composed of lignite or brown coal and peat. They represent an early stage of coal formation and they are still being formed today.
Classification of Coal
Coal can be classified into the following types according to the composition and stage of formation:
Peat (the first stage with 30 per cent carbon content).
Lignite or Brown Coal (the second stage with 30 per cent to 40 per cent carbon content).
Bituminous Coal (the third stage with 40 per cent to 80 per cent carbon content),
Anthracite (the fourth stage with 90 per cent Carbon content) and
Graphite (probably the last stage with 99 per cent carbon content and can never be used as a fuel).
Uses of Coal
Coal is a versatile mineral.
It is the most important source of power in India.
It is used in thermal generators to produce thermal power (electricity).
It is used to provide heat and raise steam in a wide range of industrial situation.
It can be used to make metallurgical coke for use in blast furnaces.
It has the advantage of converting it into other forms like gas, electricity and even oil.
Apart from its role as a source of fuel, coal provides a number of raw materials for the chemical industry, e.g. coal gas, coal tar, benzole, sulfate of ammonia and many others.
Coal is still a very important domestic fuel.
It gives by-products, such as, explosive, creosote, naphthalene, anthracene, plastics, detergents, dyes, antiseptics, adhesives, perfumes, synthetic fibres and fertilizers.
Characteristics / Features of Coal.
- Mineral.
Coal is a carbon based mineral. It also contains other molecules, such as oxygen and sulfur.
- Dark in color.
Coal usually has a very dark black color, and it may also seem to glitter. This is due to its bituminous makeup.
- Found underground.
Coal is found underground in ‘seams’. It needs to be dug out by miners in order to be used – hence coal mines were created.
- Plant based.
Coal is formed when plants die, and turn into peat when they decompose. Under pressure, and over tens of thousands of years, this pressure turns the peat into hard coal.
- Energy rich.
When burned, coal produces plenty of energy – and indeed, during the industrial revolution it was one of the main sources of energy.
- Releases carbon when burned.
Coal is a hydrocarbon and because of this, when it is burned it releases CO2 into the atmosphere.
- Limited.
Coal takes a long time to form, and yet humans are currently using up coal at a rapid rate. Some scientists have estimated that we will run out of our supply of coal by the end of the current century.
Advantages of coal.
- Easy to transport.
Though coal is only found in certain locations in the world, it is very easy to transport from one location to the next. All of the energy is stored inside the coal so (unlike other energy sources such as hydropower, which needs to be tapped into on site), coal can be brought in trucks from one end of the world to the next before it is ignited and its energy released.
- Powerful energy source.
Coal provides plenty of energy per unit, making it great for powering heavy duty machinery. Coal produces enough power to run large machinery and equipment. A few decades back, coal based trains were in vogue. However, they have now been replaced with electric powered trains.
- Provides jobs.
The coal mining industry has provided jobs throughout the world for hundreds of years.
- Suitable for domestic use.
Coal can be used in domestic wood-burning stoves as well as in large factories. However, one should remember that burning coal has a negative impact on health.
- Abundant.
Coal is one of the most abundant energy sources in the world, with China being in the lead. India is the third largest producer of coal.
- Inexpensive.
Coal is also a pretty cost effective source of energy.
- Multiple uses.
As well as providing energy, coal can also be used for purposes such as refining metals.
Disadvantages of Coal.
- Toxic by products.
The coal extraction process results in some toxic by products – arsenic, for example.
- Hazardous working conditions.
Coal miners face some very hazardous working conditions, that include breathing in toxic coal dust and risking their lives in collapsing tunnels underground.
- Dirty.
As anyone who has dropped some coal on their light colored carpet will know, coal is very dirty to store and use in a domestic setting.
- Damage to the Environment leading to Global warming.
When burned, coal emits CO2 as well as sulfides and other toxic gases. These gases contribute to the greenhouse effect and hence to global warming. Further, Coal mines can leave large scars across the landscape.
- Transportation and pollution.
Coal export and import is big business. The result of this is roads filled with noisy coal trucks emitting exhaust fumes into the air.
- Not sustainable.
Since coal has multiple uses, it is widely used across various industries. Coal based thermal power plants are among the most important means for energy generation. Our coal reserves may run out within dozens of years, estimates suggest, meaning that we cannot rely on this energy source forever.
Conclusion.
There is no denying that coal is great at giving us heat, and at converting into electricity for us to use in our homes and businesses. However, this convenience carries with it some significant environmental issues. Burning coal is very bad for the environment as it release carbon dioxide, sulfur dioxide and other harmful gases into the air. This results in health problems in humans, acid rain in the immediate vicinity of factories powered by coal, and climate change all over the world.
