Spalling in a boiler occurs in which area?

Spalling in a boiler occurs in which area?

• A. Superheater
• B. Combustion Chamber
• C. Economizer
• D. Final Stage of Furnace

Answer: (B)

Spalling is the flaking or breaking away of the boiler’s refractory lining due to thermal stresses from the flame and hot gases. In the boiler, the combustion chamber experiences the hottest temperatures and the most abrupt heat flux, so the refractory there endures repeated heating and cooling cycles. Those stress cycles foster microcracks that propagate and cause pieces of the lining to spall off. That’s why spalling is most closely associated with the combustion chamber. The superheater and economizer operate at different, typically cooler, temperature regimes and don’t undergo the same severe thermal shocks, while the final stage of the furnace is still a high-heat area but isn’t the primary site where spalling initiates.

Spalling is the flaking or breaking away of the boiler’s refractory lining due to thermal stresses from the flame and hot gases. In the boiler, the combustion chamber experiences the hottest temperatures and the most abrupt heat flux, so the refractory there endures repeated heating and cooling cycles. Those stress cycles foster microcracks that propagate and cause pieces of the lining to spall off. That’s why spalling is most closely associated with the combustion chamber. The superheater and economizer operate at different, typically cooler, temperature regimes and don’t undergo the same severe thermal shocks, while the final stage of the furnace is still a high-heat area but isn’t the primary site where spalling initiates.