What is the role of refractory in a boiler furnace?

• A. Refractory lining insulates and protects furnace walls from high temperatures
• B. Refractory increases heat transfer
• C. Refractory stores fuel
• D. Refractory cools flue gases

Answer: (A)

The role of refractory in a boiler furnace is to act as a heat-resistant lining that insulates and protects the furnace walls from the extreme temperatures and corrosive products inside the furnace. This keeps the steel shell from overheating, reduces heat loss to the walls, and resists slag attack, allowing the furnace to operate safely and efficiently. Refractory is not intended to increase heat transfer, store fuel, or cool flue gases—the materials are designed to minimize heat flow to the structure and withstand the harsh environment.