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5. Coal and Petroleum

This chapter talks about natural resources some of which are used as fuels

Nature provides us many resources for our use. For example – Air, Water and Soil. These natural resources can be classified in two categories

  1. Exhaustible Resources
  2. Inexhaustible Resources

5.1      Exhaustible Natural Resources

The resources which are present in limited quantity and can be exhausted over a period of time due to excessive human use are called as Exhaustible Natural Resources.

The examples of exhaustible resources are

  1. Coal
  2. Petroleum
  3. Natural gas

5.2      Inexhaustible Natural Resources

The resources which are present in unlimited quantity and will not be exhausted by human use are called as Inexhaustible Natural Resources

The examples of inexhaustible resources are

  1. Air
  2. Sunlight
  3. Soil

5.3      Fossil Fuels

The combustible substances, which are formed from the deal remains of living organisms, are called Fossil Fuels

For example

  1. Coal
  2. Petroleum
  3. Natural Gas

5.4      Coal

Coal is a solid fuel which is black in colour and it hard like a stone. It has multiple uses in our daily life. For example

  1. Used to power trains powered by steam engines
  2. Used in thermal power plants to produce electricity
  3. Used as a fuel in various industries like Iron and Steel manufacturing

5.4.1      How was Coal Formed

About 300 million years ago, the earth was covered with dense forests in low lying wetland areas. Due to natural calamities like flooding, these forests got buried under the soil. Over a period of time, soil got deposited over them & they got compressed. The temperature kept on rising as the forests kept on sinking deeper & deeper. Due to high pressure & high temperature, the dead plants got slowly converted into coal. Also, it is important to recall here that as coal is formed from the remains of vegetation, coal is also called a Fossil Fuel. This process of conversion of dead vegetation into coal is called as Carbonisation.

This process is called carbonization because coal mainly contains Carbon.

Coal can also be converted to other useful substances by processing. For example

  1. Coke – It is almost pure form of carbon. It is a tough, porous and black substance. It is used in the manufacture of steel and in the extraction of many metals from their ore.
  2. Coal Tar – It is a black, thick liquid with an unpleasant smell. It is mainly used in the carpeting/metalling/layering of roads. It is a mixture of about 200 substances.

The byproducts of coal tar are used as starting materials for manufacturing various substances used in everyday life & industry. For example – synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials etc.

  1. Coal Gas – It is a byproduct of Coke which is obtained during the processing of coal to get coke. It is being used as a fuel in many industries. In was used as fuel for street lighting for the first time in London in 1810 & in New York around 1820. However, these days coal gas is being used as a source of heat rather than light.

5.5      PETROLEUM

Petroleum is naturally occurring flammable liquid consisting of a complex mixture of hydrocarbons. Various usable substances are obtained from petroleum. For example

  1. Petrol
  2. Diesel
  3. Bitumen/ Coal Tar

5.5.1      How was Petroleum Formed

Petroleum was formed under the sea, millions of years ago, from dead organisms. When living organisms died, their bodies settled at the bottom of the sea & got covered with layers of sand & clay. Over the years, these were subject to high temperature and pressure and lack of air. This resulted transformation of these dead organisms into petroleum & natural gas.

Petroleum is also a fossil fuel & like all other fossil fuels, is also an inexhaustible natural resource.

5.5.2      Refining of Petroleum

The petroleum that is extracted from the oil wells cannot be used directly. In this form, petroleum is a complex mixture of various hydrocarbons like petroleum gas, petrol, diesel, lubricating oil, wax etc, which have different boiling points. It also has an unpleasant odour.

The process of separating petroleum into various constituents is called Refining. This is carried out in a petroleum refinery.

The following are the various constituents of petroleum and their uses

Constituent Uses
Liquified Petroleum Gas (LPG) Domestic Cooking Gas
Petrol Fuel for
  • Vehicles
  • Electricity generators
Diesel Fuel for
  • Vehicles
  • Electricity generators
  • Industries
Kerosene Fuel for
  • Lamps
  • Stoves
Paraffin Wax
  • Candles
  • Cosmetics (Vaseline)
  • Ointments
Bitumen
  • Carpeting of roads
  • Paints
Lubricating Oil Lubrication of industrial machinery

While refining the petroleum, many by-products are also obtained. These are called as ‘Petrochemicals’. These are used in manufacturing of following substances

  1. Detergents
  2. Fabrics (Polyester, Nylon)
  3. Polythene & plastics
  4. Fertilizers – The Hydrogen gas obtained from natural gas, is used in the production of Urea
  5. Cosmetics – The petroleum jelly commonly known as ‘Vaseline’ is used as crème to protect from chipping of skin

5.5.3      Petroleum production

World’s first oil well was dug in Pennsylvania, USA in 1859

The top 5 producers (for export or internal consumption) of Oil in the world are

  1. Saudi Arabia
  2. Russia
  3. United States
  4. Iran
  5. China

India comes at 22nd position in the list of top oil producing countries. Oil was struck for the first time in India in 1867 at Makum in Assam. In India, oil is found in Assam, Gujarat, Mumbai High and in the river basins of Godavari & Krishna.

Top exporters of Oil in the world are

  1. Saudi Arabia
  2. Russia
  3. Norway
  4. Iran
  5. United Arab Emirates (UAE)

5.6      Natural Gases

Natural gas is a combustible gas, mainly consisting of Methane and small amounts of other hydrocarbons like ethane. Natural gas is stored under high pressure, so it is called as CNG (Compressed Natural Gas). It is considered to be a cleaner fuel as it does not pollute the environment.

5.6.1      How was Natural Gas Formed

Natural Gas is also a fossil fuel, which is commercially found/produced in

  1. Coal fields
  2. Oil fields
  3. Natural Gas fields

5.6.2      Refining of Natural Gas

Natural Gas is refined to separate Methane from rest of the hydrocarbons. The combustible part of the gas is liquefied using Gas-to-Liquid technology and transported using pipes, for Industrial and Domestic uses.

5.6.3      Natural Gas production

The top 5 Natural Gas producing countries in the world are

  1. Russia
  2. United States
  3. Canada
  4. Iran
  5. Norway

India comes at 15th position in the list of oil producing companies. In India, we have vast reserves of Natural Gas located in Tripura, Rajasthan, Maharashtra and in Krishna Godavari delta.

5.7      Conservation of Natural Resources

The exhaustible natural resources are limited. Fossil fuels took millions of years to be in the present form, so if we abuse these natural resources, we will run out of them.

Also, burning of fossil fuels leads to air pollution which leads to global warming & thus an imbalance in the ecosystem.

We must do our bit to save our environment and conserve fuels. Petroleum Conservation Research Association (PCRA) advises following measures to save fuel

  1. Drive your vehicle at a constant & moderate speed
  2. Switch off the engine at traffic light
  3. Ensure correct tyre pressure
  4. Ensure regular maintenance of your vehicle