What component of a boiler is primarily affected by spalling?

Spalling is a process where material, often ceramic or concrete, fractures and breaks off due to high temperatures and thermal cycling. In the context of a boiler, the component primarily affected by spalling is the combustion chamber. The combustion chamber is where the fuel is burned to produce heat, and it must withstand extremely high temperatures. Over time, the intense heat can cause the lining materials of the combustion chamber to expand and contract, leading to spalling as the materials degrade and lose their structural integrity.

This degradation can compromise the efficiency of the combustion process and ultimately lead to increased maintenance needs or even failures if not addressed. In contrast, while the other components like heat exchangers, feedwater tanks, and steam drums do experience wear and stress, they are not primarily susceptible to spalling in the same way that combustion chambers are.