Context
New IIT-D study has challenged need for flue gas desulfurization in thermal power plants
About Flue Gas De-sulphurisation (FGD):
- Flue gas is the mixture of gases emitted when fossil fuels such as coal, oil, natural gas, or wood are burned for heat or power.
- FGD is a process to remove sulphur dioxide (SO₂) from flue gas of fossil-fuel power plants and other industries emitting SO₂.
- SO₂ Removal: Removes sulphur dioxide from exhaust gases to meet emission standards.
- Environmental Impact: Reduces SO₂ emissions, curbing acid rain, smog, and respiratory diseases.
- FGD Working:
- Sorbent Use: Lime or limestone reacts with SO₂ to convert it into harmless products.
- Injection Methods: Sorbent can be injected as:
- Dry powder
- Wet slurry
- Seawater solution
- Residue Collection: Reaction products are collected as solid residues, dissolved in water, or discharged into the sea.
- Importance of FGD:
- Environmental Benefits:
- Reduces acid rain that damages forests, lakes, soil, buildings, and aquatic life.
- Lowers formation of secondary pollutants (e.g., sulphate aerosols), improving visibility and reducing atmospheric radiation.
- Health Benefits:
- Prevents respiratory issues like asthma, bronchitis, and COPD.
- Reduces risks of respiratory infections, cardiovascular diseases, and lung cancer from prolonged exposure to SO₂.
- Environmental Benefits:
- Types of FGD Systems:
- Wet Scrubbing
- Spray-Dry Scrubbing
- Wet Sulphuric Acid Process
- Dry Sorbent Injection
Source: DTE
Previous Year Question
In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?
Carbon dioxide
Carbon monoxide
Nitrogen dioxide
Sulfur dioxide
Methane
Select the correct answer using the code given below:
[UPSC Civil Services Exam – 2016 Prelims]
(a) 1, 2 and 3 only
(b) 2, 3 and 4 only
(c) 1, 4 and 5 only
(d) 1, 2, 3, 4 and 5
Answer: (b)
