Air Pollution MCQ with answer and solution

Concept

Pulverised coal injection (PCI) puts cheap coal powder into the blast furnace tuyeres and replaces part of the costly, energy-heavy coke.

Step-by-step solution

1. In a blast furnace, coke gives heat and acts as the reducing agent. 2. Making coke in coke ovens uses a lot of energy and causes pollution. 3. PCI injects powdered coal directly at the tuyeres, so less coke is needed. 4. This reduces the coke rate, saves energy and cuts emissions. 5. The other options save energy in other units, but they do not replace the coke charge. 6. So the answer is A.

Explanation

Pulverised coal injection replaces part of the coke used in the blast furnace with cheaper coal powder. This saves energy because less coke has to be made in coke ovens. It is the standard substitute technique in steel plants.

Why the other options are wrong

B: Programmed coke heating only saves fuel inside the coke oven. C: Heat recovery from hot sinter only reuses waste heat in the sinter plant. D: Coke dry quenching only recovers heat from hot coke. None of these three replaces the blast furnace or its coke.

Shortcut

Substitute for coke in blast furnace = PCI.

Common mistake

Choosing dry quenching or sinter heat recovery. These are energy-saving steps, but they are not substitutes.