Chapter 3: Coal and Petroleum
Natural Resources
Resources that are obtained from nature are called natural resources. They are classified into two main types based on their availability.
1. Inexhaustible Natural Resources
These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities.
Examples: Sunlight, Air.
2. Exhaustible Natural Resources
The amount of these resources in nature is limited. They can be exhausted by human activities over time.
Examples: Forests, Wildlife, Minerals, Coal, Petroleum, Natural Gas.
Fossil Fuels
Coal, petroleum, and natural gas are known as fossil fuels. They are exhaustible natural resources formed from the dead remains of living organisms (fossils) over millions of years.
Coal: The Buried Sunshine
Formation of Coal
About 300 million years ago, dense forests in low-lying wetland areas got buried under the earth. Due to high pressure and high temperature, the dead vegetation slowly converted to coal. This slow process of conversion of dead vegetation into coal is called carbonisation.
Products from Coal
When processed in industry, coal yields several useful products:
- Coke: A tough, porous, and black substance. It is an almost pure form of carbon, used in steel manufacturing and metal extraction.
- Coal Tar: A black, thick liquid with an unpleasant smell. It is a mixture of about 200 substances, used for making synthetic dyes, drugs, explosives, and plastics. Naphthalene balls are a product of coal tar.
- Coal Gas: Obtained during the processing of coal to get coke. It is used as a fuel in many industries.
Petroleum: The Liquid Gold
Formation of Petroleum
Petroleum was formed from organisms living in the sea. As these organisms died, their bodies settled at the bottom of the sea and got covered with layers of sand and clay. Over millions of years, under high temperature and pressure, these dead organisms transformed into petroleum and natural gas.
Refining of Petroleum
Petroleum is a dark, oily liquid. The process of separating its various constituents/fractions is known as refining. This is carried out in a petroleum refinery.
| Constituent of Petroleum | Uses |
|---|---|
| LPG (Liquefied Petroleum Gas) | Fuel for home and industry |
| Petrol | Motor fuel, aviation fuel, solvent for dry cleaning |
| Kerosene | Fuel for stoves, lamps, and for jet aircrafts |
| Diesel | Fuel for heavy motor vehicles, electric generators |
| Lubricating Oil | Lubrication |
| Paraffin Wax | Ointments, candles, vaseline etc. |
| Bitumen | Paints, road surfacing |
Natural Gas
Natural gas is a very important fossil fuel because it is easy to transport through pipes. It is stored under high pressure as Compressed Natural Gas (CNG).
- Uses: CNG is used for power generation and as a cleaner fuel for vehicles.
- Advantages: It is less polluting and can be supplied directly to homes and factories through a network of pipelines.
Conservation of Fossil Fuels
Fossil fuels are exhaustible and take millions of years to form. Their burning is a major cause of air pollution and global warming. Therefore, it is essential to use these fuels judiciously.
In India, the Petroleum Conservation Research Association (PCRA) advises people on how to save petrol/diesel while driving. Tips include driving at a constant and moderate speed, switching off the engine at traffic lights, and ensuring correct tyre pressure.
Frequently Asked Questions (FAQ)
What are fossil fuels?
Fossil fuels are natural fuels, such as coal, petroleum, and natural gas, formed in the geological past from the remains of living organisms.
What is carbonisation?
It is the very slow process of conversion of dead vegetation buried under the earth into coal, under conditions of high temperature and pressure.
Why is CNG considered a cleaner fuel?
CNG is considered a cleaner fuel because it produces significantly fewer harmful gases like carbon dioxide and pollutants upon burning compared to petrol and diesel.
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