Fossil Fuels: Coal, Petroleum, and Natural Gas

• Coal, Petroleum, and Natural Gas are exhaustible natural resources, categorized as fossil fuels.
• Fossil fuels are made from fossils, which are the dead remains of living organisms.
• A fuel is any substance releasing energy as heat and light when burned, like coal and petroleum.
• Fuels can be solids at room temperature, like coal, firewood, animal dung, charcoal and coke.
• Fuels can be volatile liquids that produce vapor, which burns and produces energy, such as petrol, diesel and kerosene.
• Fuels can be gases, or mixtures of gases like natural gas and biogas.

Uses of Fossil Fuels

• Fuels power transportation vehicles like cars, trucks, motorcycles, trains, and airplanes.
• Fuels are required for cooking, with LPG used in urban areas and firewood, coal, and cattle dung in rural areas.
• Fuels generate heat.
• Fuels such as coal, petrol, natural gas, & diesel are used for electricity production.
• Fuels run machinery, provide heating, and generate electricity in industries.
• Fuels, i.e. propellants, are used in rockets to launch space vehicles.

Characteristics of a Good Fuel

• It should be economical and easily available.
• It should not emit poisonous gases when burning.
• It should produce large amounts of heat relative to its mass, having a high calorific value.
• It should be easy to transport and handle and should not produce a bad odor.
• It should be clean, should not produce many ashes, and should not ignite easily at room temperature.

Coal Formation and Composition

• Coal is a fossil fuel formed from dead plant matter over millions of years due to heat and pressure.
• Coal forms through biological and geological processes on dead and decaying plant matter over millions of years.
• Coal mainly contains carbon, and the conversion of dead vegetation into coal is called carbonisation.
• Coal consists of hydrogen, carbon, oxygen, and a small amount of sulphur.

Coal Mining

• Coal is extracted through mining, which can be either opencast or underground.
• Opencast mining extracts coal from near the Earth's surface.
• Underground Mining extracts coal from deep inside the Earth's crust.
• As it ages, coal has a higher carbon content. When burnt, it releases carbon dioxide.

Coal Uses

• Coal is used as fuel for cooking, for electricity production in thermal power plants, and in various industries.
• Coal was once used to run steam-powered railway engines.
• Processed coal yields coke, coal tar, and coal gas, which are used by many industries.

Destructive Distillation

• Destructive distillation is the process of heating coal at very high temperatures in the absence of air to obtain products like coal gas, coal tar, coke, and liquor ammonia.
• Hydrocarbons, such as methane, butane, and hexane consist of only carbon and hydrogen and are produced on burning of the fossil fuels.
• Coal is a major energy source in industries and rural areas; it has other uses like the synthesis of synthetic oil, natural gas, coke, coal tar and gas.

Burning Coal

• Burning coal releases carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen, lead, arsenic, and mercury.
• The term "Petroleum" comes from "Petra" (rock) and "oleum" (oil); it is extracted from rocks underneath the Earth.
• Petroleum, also known as crude oil, forms from the remains of ancient marine organisms.

Petroleum and Natural Gas

• When sea organisms die, their bodies sink and are covered by layers of sand and clay.
• Over millions of years, these remains transform into petroleum and natural gas due to high temperature, high pressure, and absence of air.
• Natural gas is found above crude oil in oil wells because gas and oil are lighter than water and do not mix.
• The first oil well in the world was drilled in Pennsylvania, USA, in 1859.
• The second oil well in the world was drilled in Makum, Assam, India in 1867.
• In India, oil is found in Assam, Gujarat, Mumbai High, and the river basins of Godavari and Krishna.

Petroleum Refining

• Petroleum consists of petrol, diesel, petroleum fas, paraffin wax, lubricating oil etc.
• Petroleum is a dark, oily liquid with an unpleasant odour.
• Refining petroleum is the process of separating its constituents.
• This refining process occurs in a petroleum refinery.
• Petroleum yields several commercially successful substances and is called "black gold".
• Products obtained from petroleum and natural gas are called 'petrochemicals'.

Petrochemicals

• Petrochemicals are used in manufacturing synthetic fibres (Polyester, Nylon, Acrylic), detergents, polythene, & man made plastics.
• Natural gas yields Hydrogen gas which is used in the production of fertilisers (such as urea).

Natural Gas

• Natural gas is a naturally occurring fossil fuel, a hydrocarbon gas mixture in oil wells.
• Natural gas is mainly methane but can contain varying amounts of other higher alkanes, carbon dioxide, helium, nitrogen, and hydrogen sulphide.
• Natural gas is easily transported through pipes; it is stored as CNG (compressed natural gas) for chemical and fertilizer manufacturing.
• Natural gas does not cause pollution and has a high calorific value.
• Compressed Natural Gas (CNG) is stored under high pressure.
• CNG is used to generate power, for transport vehicles (cleaner than petrol/diesel), and as fuel in homes/industries.
• CNG pipeline networks exist in Vadodara, Gujarat, Delhi, as well as other places.
• Natural gas is considered a better and cleaner fuel than coal and petroleum because it causes less pollution.
• Natural gas emits 50% less carbon dioxide, sulphur, and nitrogen oxides.
• Vast reserves of natural gas in India are found in Maharashtra, Rajasthan, Tripura, and the River Delta of Krishna and Godavari.

Natural Resources

• Fossil fuels like coal, petroleum, and natural gas cannot be created in the laboratory and take thousands of years to form so natural resources are considered limited.
• Burning fossil fuels causes an increase in air pollution due to unburnt carbon particles, carbon monoxide, and sulphur dioxide.
• Burning fossil fuels can also lead to global warming the the release of large amounts of carbon dioxide.

PCRA

• Fossil fuels are exhaustible and take hundreds/thousands of years to replenish.
• Fossil fuels consumption is increasing rapidly and may be completely depleted in 100 years.
• According to the Petroleum Conservation Research Association (PCRA) in India, one can save petrol/diesel by:
  • Driving at a constant/moderate speed.
  • Maintaining correct tyre pressure.
  • Switching off the engine.
  • Doing regular vehicle maintenance.