COAL at a glance

SEO Keywords

• Coal formation stages
• Types of coal and uses
• Properties of coal
• Coalification process
• Anthracite vs bituminous coal
• Fossil fuels explained

Introduction

Coal is a fossil fuel formed from the remains of plants that lived millions of years ago. It is mainly composed of carbon and is one of the most important sources of energy used for electricity generation and industrial processes.

Coal is formed through a slow process called carbonization, where plant materials are buried under sediments and exposed to heat and pressure over time.

Formation of Coal

Coal formation began during ancient geological periods such as the , when dense forests existed.

Process of Formation

1. Plants absorb carbon dioxide during photosynthesis.
2. Dead plants accumulate in swampy areas.
3. Layers of sediment cover the plant material.
4. Heat and pressure increase over millions of years.
5. Gradual conversion into different forms of coal.

Stages of Coal Formation (Coalification)

Coal forms in stages, with increasing carbon content and energy value:

1. Peat  This is the first stage of coal formation ( also known as coal in the making)

It Contains partially decayed plant material

i. It has Low carbon content (~50–60%)

• High moisture content
• Burns with a lot of smoke

2. Lignite (Brown Coal)

• Soft and brown in color
• Higher carbon content than peat (~60–70%)
• Low heating value
• Contains moisture

3. Bituminous Coal

• Most commonly used coal
• Black and relatively hard
• Higher carbon content (~70–85%)
• Produces more heat
• Used in industries and electricity generation

4. Anthracite

• Highest grade of coal
• Very hard and shiny
• Highest carbon content (~90–95%)
• Burns with a clean, smokeless flame
• Highest energy value

Types of Coal

Coal is generally classified based on its carbon content and energy value:

Type	Carbon Content	Characteristics	Uses
Peat	Low	Soft, moist	Limited fuel
Lignite	Moderate	Brown, crumbly	Power generation
Bituminous	High	Black, widely available	Industrial fuel
Anthracite	Very high	Hard, clean burning	Domestic & industrial

Properties of Coal

1. Physical Properties

• Color: Brown to black
• Texture: Soft (peat) to hard (anthracite)
• Lustre: Dull to shiny
• Density: Increases with carbon content

2. Chemical Properties

• Mainly composed of carbon, with hydrogen, oxygen, nitrogen, and sulfur
• Produces carbon dioxide (CO₂) when burned
• May release sulfur compounds causing pollution

3. Combustion Properties

• Burns to produce heat energy
• Calorific value increases from peat → anthracite
• Some types produce smoke and soot

4. Coking Property

• Certain coals (especially bituminous) can soften and form coke when heated in the absence of air
• Coke is used in iron and steel production

Uses of Coal

• Generation of electricity in power plants
• Production of coke for metallurgy
• Industrial fuel
• Production of chemicals such as coal tar and ammonia

Advantages of Coal

• Abundant and relatively cheap
• High energy output
• Easy to store and transport

Disadvantages of Coal

• Non-renewable resource
• Causes air pollution (CO₂, SO₂ emissions)
• Contributes to global warming
• Mining can damage the environment

Conclusion

Coal remains a major energy source worldwide despite environmental concerns. Understanding its stages, types, and properties helps explain its wide range of uses and its impact on the environment.

Objectives questions 

1. Coal is primarily composed of
   A. Hydrogen
   B. Carbon
   C. Oxygen
   D. Nitrogen

2. The process by which coal is formed from plant remains is called
   A. Distillation
   B. Carbonization
   C. Combustion
   D. Crystallization

3. Which of the following is the lowest grade of coal?
   A. Anthracite
   B. Bituminous
   C. Lignite
   D. Peat

4. The highest grade of coal with the highest carbon content is
   A. Lignite
   B. Peat
   C. Anthracite
   D. Coke

5. Which type of coal is most commonly used in industries?
   A. Peat
   B. Lignite
   C. Bituminous
   D. Anthracite

6. Coal that burns with little or no smoke is
   A. Lignite
   B. Bituminous
   C. Anthracite
   D. Peat

7. The stage that comes immediately after peat in coal formation is
   A. Anthracite
   B. Lignite
   C. Coke
   D. Charcoal

8. Which of the following products is obtained from coal processing?
   A. Ethanol
   B. Coal tar
   C. Glucose
   D. Methane

9. The formation of coke from coal involves heating in the absence of
   A. Water
   B. Oxygen
   C. Nitrogen
   D. Hydrogen

10. Which of the following is a disadvantage of coal?
    A. High energy output
    B. Easy storage
    C. Causes air pollution
    D. Abundant supply

Answer Key

1. B
2. B
3. D
4. C
5. C
6. C
7. B
8. B
9. B
10. C