UPSC Prelims 2021 Q18: Furnace Oil — Source, Uses, Pollution
With reference to furnace oil, consider the following statements:
1. It is a product of oil refineries.
2. Some industries use it to generate power.
3. Its use causes sulphur emissions into environment.
Which of the statements given above are correct?
- 1 and 2 only
- 2 and 3 only
- 1 and 3 only
- 1, 2 and 3
Answer: (d) 1, 2 and 3
Statement-wise explanation
- 1: correct — Furnace oil is a residual fuel oil. It is the heavy, thick fraction left at the bottom after crude oil is distilled in a refinery and the lighter products (LPG, petrol, naphtha, kerosene, diesel) have been taken off. Indian refineries make and sell it alongside their other petroleum products, so it is a refinery product.
- 2: correct — Industries burn furnace oil in boilers, furnaces and captive generating sets to produce heat, steam and electricity. A 2017 Union Environment Ministry reply in Parliament, released through PIB, named cement, fertiliser, ceramics and glass among the industries that burn pet coke and furnace oil. Small oil-fired captive power units also run on it.
- 3: correct — Furnace oil comes from the heaviest part of crude oil, where most of the sulphur collects, so it has a high sulphur content. When it burns, the sulphur becomes sulphur dioxide, which also forms secondary particulate matter in the air. For this reason the Supreme Court in October 2017 barred industries in Uttar Pradesh, Haryana and Rajasthan from using pet coke and furnace oil, after their use had already been stopped in Delhi.
How to eliminate
This question is mostly common sense once you know what furnace oil is. The name tells you it is an oil burnt in furnaces, so Statement 2 (industries burn it for energy) is very likely true. Every oil fuel sold in India comes from crude oil, and crude oil is processed in refineries, so Statement 1 is safe. Statement 3 has no absolute word such as 'only' or 'always'. It says only that its use causes sulphur emissions, and almost every crude-derived fuel contains some sulphur, the heavy residual fuels most of all. With nothing in any statement that sounds extreme, the all-three option is the natural choice. Fact to remember: furnace oil is a heavy residual fuel from refineries, used for industrial heat and power, and it is high in sulphur. That is why it sits with pet coke on the 'banned in NCR' list.
Know more
Furnace oil and the bottom of the barrel
In a refinery, crude oil is heated and separated by boiling point. Light gases and petrol rise to the top of the column. Kerosene, jet fuel and diesel come off in the middle. The heavy residue that stays at the bottom becomes fuel oil (furnace oil), bitumen and, after further cracking, petroleum coke (pet coke). Sulphur and metals in crude oil collect in this heavy end, so the bottom-of-the-barrel fuels are the dirtiest.
| Fuel | Where it comes from | Main users | Pollution concern |
|---|---|---|---|
| LPG / natural gas | Top of the column / gas fields | Homes, industry, CNG transport | Low SO₂ |
| Diesel (BS-VI) | Middle distillate | Vehicles, gensets | Sulphur capped at 10 ppm |
| Furnace oil / LSHS | Residue | Boilers, furnaces, captive power, ships | High SO₂, particulates |
| Pet coke | Cracked residue | Cement kilns, lime, power | Very high sulphur |
How India regulates these fuels
- Supreme Court (2017): pet coke and furnace oil were stopped in Delhi, then in industries of UP, Haryana and Rajasthan. Cement and some other processes later got limited exemptions.
- Commission for Air Quality Management (CAQM): created by ordinance in 2020 and made law by an Act of Parliament in 2021. It later issued a standard list of approved fuels for NCR that leaves out furnace oil and coal.
- Shipping: the International Maritime Organization's limit of 0.5% sulphur in marine fuel took effect on 1 January 2020. It pushed refiners, including Indian ones, to make very low sulphur fuel oil (VLSFO).
The cleaner substitutes are natural gas (piped natural gas, PNG) and electrifying industrial heat, for example with heat pumps.
In the news
Sulphur-heavy industrial fuels were in the news before the 2021 exam. The Supreme Court's pet coke and furnace oil bans for Delhi-NCR were being applied, the Commission for Air Quality Management was set up by ordinance in 2020 and by an Act in 2021, and the IMO's 0.5% sulphur cap on marine fuel oil took effect on 1 January 2020.
NCERT Concepts to Revise
- Natural gas: Natural gas is the low-sulphur fuel NCR industries were moved to as furnace oil and pet coke were restricted.