📘 Q.2 IAS Prelims 2021 — Environment & Ecology (Furnace Oil)🧷 Authentic Classroom Explanation by IAS Monk
📌 The Question:
With reference to furnace oil, consider the following statements:
- It is a product of oil refineries.
- Some industries use it to generate power.
- Its use causes sulphur emissions into the environment.
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
✅ Correct Answer: (d) 1, 2 and 3
🧠 Classroom Explanation:
🔹 Statement 1 – Correct
Furnace oil (also called heavy fuel oil / bunker fuel) is a residual fraction obtained during petroleum refining. It is thicker, heavier, and cheaper than lighter fuels like petrol or diesel.
🔹 Statement 2 – Correct
Several industrial units and power plants use furnace oil to generate power, especially:
• Captive power plants
• Diesel Generator Power Plants (DGPPs)
• Industrial boilers and furnaces
(Example: Basin Bridge DG Power Plant, Tamil Nadu)
🔹 Statement 3 – Correct
Furnace oil has high sulphur content. During combustion:
• Sulphur → SO₂ (Sulphur dioxide)
• Small fraction → SO₃ (Sulphur trioxide)
These SOx emissions contribute to:
• Acid rain
• Respiratory diseases
• Industrial smog
Hence, all three statements are correct.
🔍 Curiosity Raiser:
Why did many Indian cities ban furnace oil?
👉 Because it was one of the largest contributors to urban SO₂ pollution, especially before the push towards natural gas and low-sulphur fuels.
📚 Enrich Notes (Prelims Edge):
• Furnace oil = residual petroleum product
• High sulphur → SO₂ → Acid rain
• IMO norms now restrict sulphur in marine fuels
• Shift underway to LSFO, LNG, renewables
Quick Memory Hook:
👉 “Furnace oil = Heavy + Cheap + Dirty”
🪶 IAS Monk Whisper:
When energy is drawn from the darkest residues, the sky pays the price.