Coal and Petroleum: Comprehensive Study Notes

3.1 Coal

  • Natural resources can be classified as:
    • Inexhaustible Natural Resources: present in unlimited quantity; not likely to be exhausted by human activities (examples: sunlight, air).
    • Exhaustible Natural Resources: limited in nature; can be exhausted by human activities (examples: forests, wildlife, minerals, coal, petroleum, natural gas).
  • Activity 3.1: Classify daily-life materials into Natural vs. Man-made. Example in the transcript involves listing materials used by us and categorizing them as natural or man-made.
  • Question raised: Can we use all natural resources forever? Air, water, soil, and minerals are natural resources obtained from nature.
  • Activity 3.2 (Group activity): Demonstrates consumption of a finite resource across generations (first, second, third generation) using a container of eatables as a model for resource availability. Observations focus on whether the third generation gets enough and whether earlier generations were greedy.
  • Fossil fuels introduction: Coal, petroleum, and natural gas are exhaustible natural resources formed from dead remains of living organisms (fossils).
  • 3.1 Coal: overview
    • Coal is hard, black, and a fuel used to cook, in railway steam engines (historical), and in thermal power plants for electricity.
    • Story of Coal (formation): About 300 million years ago, dense forests in wetlands got buried under soil. Over time, more soil deposited, leading to compression and rising temperature as depth increased. Under high pressure and temperature, dead plants slowly converted to coal. This slow process is called carbonisation. Since coal comes from plant remains, it is a fossil fuel.
    • Coal mine illustration reference: Fig. 3.2 (coal mine).
  • Coal-derived products and processes
    • Coal Gas: Obtained during processing of coal to coke. Used for heat and earlier for street lighting; first used for street lighting in London (1810) and New York (1820). Nowadays primarily a heat source.
    • Coal Tar: A black, thick liquid (~200 substances) obtained from coal tar; used as starting materials for synthetic dyes, drugs, explosives, perfumes, plastics, paints, roofing materials, etc. Also used to produce naphthalene balls (moth repellent) from coal tar.
    • Coke: A tough, porous, nearly pure carbon product obtained from coal; used in steel manufacture and in metal extraction.
    • Bitumen: A petroleum product used in road metalling, replacing coal tar for road surfacing.
    • Coal’s combustion: When coal is heated in air, it burns to produce mainly carbon dioxide (CO2):
      extC+extO<em>2ightarrowextCO</em>2ext{C} + ext{O}<em>2 ightarrow ext{CO}</em>2
  • 3.2 Petroleum
    • Uses of petroleum-derived fuels:
    • Petrol is used as fuel in light vehicles (motorcycles/scooters, cars).
    • Diesel is used by heavy motor vehicles (trucks, tractors).
    • Formation of petroleum
    • Formed from organisms living in the sea. When these organisms died, their bodies settled at the sea bottom and were covered by layers of sand and clay. Over millions of years, due to absence of air, high temperature, and high pressure, the dead organisms transformed into petroleum and natural gas.
    • Deposits and cutting layers
    • Deposits show petroleum and natural gas above water since oil and gas are lighter than water and do not mix with it.
    • Wells: The world’s first oil well drilled in Pennsylvania, USA, in 1859; oil struck at Makum in Assam in 1867.
    • In India, oil is found in Assam, Gujarat, Mumbai High, and in river basins of Godavari and Krishna.
    • Refining and products
    • Refining: Separation of the various constituents/fractions of petroleum is called refining; carried out in a petroleum refinery (Fig. 3.5).
    • Petroleum is a dark, oily liquid with an unpleasant odour; it is a mixture of constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc.
    • Petrochemicals: Many useful substances obtained from petroleum and natural gas used to manufacture detergents, fibers (polyester, nylon, acrylic), polythene, and other plastics.
    • Hydrogen gas obtained from natural gas is used in the production of fertilisers (urea).
    • Petroleum is often called ‘black gold’ due to its great commercial importance.
    • Constituents of petroleum and their uses (Table 3.1 summarized):
    • Petroleum Gas (in liquid form): LPG — Fuel for home and industry.
    • Petrol: Motor fuel; aviation fuel; solvent for dry cleaning.
    • Kerosene: Fuel for stoves, lamps, and jet aircraft.
    • Diesel: Fuel for heavy motor vehicles and electric generators.
    • Lubricating oil: Lubrication.
    • Paraffin wax: Ointments, candles, Vaseline, etc.
    • Bitumen: Paints, road surfacing.
    • Refinery illustration reference: Fig. 3.5.
  • 3.3 Natural Gas
    • Natural gas is a fossil fuel that is easy to transport through pipelines.
    • Storage: Stored under high pressure as compressed natural gas (CNG).
    • Uses:
    • CNG is used for power generation.
    • Cleaner fuel for transport vehicles; network of pipelines enables direct burning in homes and factories.
    • Pipeline networks in India: Vadodara (Gujarat), some parts of Delhi, and other locations.
    • Starting material for chemicals and fertilisers.
    • Reserves in India: Vast reserves; found in Tripura, Rajasthan, Maharashtra, and Krishna Godavari delta.
  • 3.4 Some Natural Resources are Limited
    • Recap: Some natural resources (coal, petroleum, natural gas) are exhaustible; coal and petroleum are fossil fuels formed over millions of years; known reserves will last only a few hundred years.
    • Environmental concerns: Burning fossil fuels is a major source of air pollution and is linked to global warming.
    • Conservation message: Use fossil fuels only when absolutely necessary to prolong availability and protect the environment.
    • PCRA tips for petrol/diesel conservation while driving (Driving Energy Conservation):
    • Drive at a constant and moderate speed as far as possible.
    • Switch off the engine at traffic lights or places where you must wait.
    • Ensure correct tyre pressure.
    • Ensure regular maintenance of the vehicle.
  • Can coal, petroleum, and natural gas be prepared in the laboratory from dead organisms?
    • No. Their formation is extremely slow and conditions cannot be recreated in the laboratory.
  • 2024-25 (contextual note about the material’s edition/date)

3.1 Coal: Key Concepts and Details (condensed)

  • Coal is formed from dead vegetation via carbonisation under high pressure and temperature over millions of years.
  • Major coal-derived products: coke, coal tar, coal gas.
  • Coal tar contains about 200 substances and is a source for many everyday-use and industrial chemicals.
  • Coal gas historically provided street lighting; now primarily used as a heat source.
  • Bitumen is a petroleum product used for road surfacing, replacing coal tar in modern applications.
  • The coal–petroleum–natural gas system emphasizes how fossil fuels supply energy and materials, but finite in availability and environmental impact.

3.2 Petroleum and its Refining

  • Petroleum formation: marine organisms buried under sediment, transformed by heat and pressure over geologic time.
  • Natural gas and petroleum are often found together in reservoirs with oil/gas layers floating above water due to density differences.
  • Oil exploration milestones: 1859 (Pennsylvania, world’s first oil well); 1867 (Makum, Assam, oil struck).
  • Indian oil locations: Assam, Gujarat, Mumbai High, Godavari and Krishna river basins.
  • Refining process: separation of petroleum into various fractions; production of petrochemicals.
  • Uses of refinery products:
    • LPG (petroleum gas) as domestic/industrial fuel.
    • Petrol as motor fuel; aviation fuel; solvent.
    • Kerosene for stoves, lamps, jet aircraft.
    • Diesel for heavy vehicles and power generators.
    • Lubricating oil for machinery.
    • Paraffin wax for ointments, candles, Vaseline.
    • Bitumen for paints and road surfacing.
  • Petrochemicals and plastics: Detergents, polyesters, nylons, acrylics, polythene.
  • Hydrogen from natural gas used to manufacture fertilisers (urea).
  • Natural gas as a cleaner energy source; CNG and pipeline infrastructure.
  • “Black gold”: petroleum’s significant economic importance in modern society.

3.3 Natural Gas

  • Distinct advantages:
    • Easy to transport via pipelines; stored as CNG under high pressure.
    • Cleaner burning than many alternatives; reduces pollution and greenhouse effects.
  • Uses of CNG: power generation, transport fuel, domestic/industrial heating via pipelines.
  • Geographic and resource notes:
    • Pipelines networks in specific Indian cities (e.g., Vadodara, Delhi).
    • Major reserves located in multiple states (Tripura, Rajasthan, Maharashtra) and Krishna Godavari delta region.
  • Role in chemical industry: hydrogen from natural gas as feedstock for fertilisers (urea) and other chemicals.

3.4 Some Natural Resources are Limited (Summary)

  • Fossil fuels are exhaustible resources formed over millions of years from dead organisms.
  • Known reserves are finite; consumption patterns affect availability and environmental health.
  • Environmental concerns: burning fossil fuels contributes to air pollution and global warming; therefore, judicious use is essential.
  • Conservation tips from PCRA:
    • Drive at a constant, moderate speed.
    • Switch off engine at waits/traffic lights.
    • Maintain correct tyre pressure.
    • Regular vehicle maintenance to improve efficiency.
  • Scientific note: Coal, petroleum, and natural gas cannot be synthesized quickly in laboratories; their formation requires long geologic processes.

Key Words

  • COAL
  • COAL GAS
  • COAL TAR
  • COKE
  • FOSSIL FUEL
  • NATURAL GAS
  • PETROLEUM
  • PETROLEUM REFINERY

What You Have Learnt

  • Coal, petroleum and natural gas are fossil fuels.
  • Fossil fuels formed from dead remains of living organisms millions of years ago.
  • Fossil fuels are exhaustible resources.
  • Coke, coal tar and coal gas are products of coal.
  • Petroleum yields include petroleum gas, petrol, diesel, kerosene, paraffin wax, lubricating oil after refining.
  • Coal and petroleum resources are finite; judicious use is necessary.

Exercises

  1. What are the advantages of using CNG and LPG as fuels?
  2. Name the petroleum product used for road surfacing.
  3. Describe how coal is formed from dead vegetation. What is this process called?
  4. Fill in the blanks:
    (a) Fossil fuels are ___, ___ and ___.
    (b) The process of separation of different constituents from petroleum is called ___.
    (c) The least polluting fuel for vehicles is ___.
  5. True/False:
    (a) Fossil fuels can be made in the laboratory. (T/F)
    (b) CNG is more polluting than petrol. (T/F)
    (c) Coke is almost a pure form of carbon. (T/F)
    (d) Coal tar is a mixture of various substances. (T/F)
    (e) Kerosene is not a fossil fuel. (T/F)
  6. Explain why fossil fuels are exhaustible natural resources.
  7. Describe characteristics and uses of coke.
  8. Explain the process of formation of petroleum.
  9. The following table shows total power shortage in India from 1991–1997. Plot shortage percentage vs year on a graph (shortage % by year).
    1991: 7.9; 1992: 7.8; 1993: 8.3; 1994: 7.4; 1995: 7.1; 1996: 9.2; 1997: 11.5

Extended Learning — Activities and Projects

  1. Obtain an outline map of India. Mark coal, petroleum, natural gas locations and locations of petroleum refineries.
  2. Survey five families to see whether their energy consumption (coal, gas, electricity, petrol, kerosene) has increased or decreased in the last five years and note conservation measures they adopt.
  3. Find the locations of major thermal power plants in India and reason about their locations.

Illustrations referenced in the text (for context)

  • Fig. 3.1: Visual of coal appearance and form.
  • Fig. 3.2: A coal mine depiction.
  • Fig. 3.3: Coal tar illustration.
  • Fig. 3.4: Petroleum and natural gas deposits cross-section (layered reservoirs).
  • Fig. 3.5: A petroleum refinery schematic.

Notable numeric references

  • 300 million years ago: time frame for coal formation from forests.
  • 1859: World’s first oil well drilled in Pennsylvania.
  • 1867: Oil struck at Makum, Assam.
  • 200 substances: approximate number of substances in coal tar.
  • Population/consumption group sizes in Activity 3.2: first generation (1), second generation (2), third generation (4).
  • Pipeline and network references: Vadodara (Gujarat), some parts of Delhi, etc.
  • Regional reserves and locations for natural gas in India: Tripura, Rajasthan, Maharashtra, Krishna Godavari delta.
  • Common chemical reactions and processes (illustrated by formation and burning):
    • Combustion of coal: extC+extO<em>2ightarrowextCO</em>2ext{C} + ext{O}<em>2 ightarrow ext{CO}</em>2
    • Refining and separation processes summarized but not exhaustively listed here.