Boiler water with high alkalinity could develop which of the following issues?

High alkalinity in boiler water can lead to a phenomenon known as caustic embrittlement. This issue occurs when an increase in the concentration of hydroxyl ions (OH-) leads to the weakening of the metal structure, particularly in low-alloy steel and wrought iron. When caustic soda (sodium hydroxide) is present in high concentrations, it can penetrate the surface of the metal and create conditions that promote cracking or embrittlement, particularly under stress.

Caustic embrittlement is notably problematic because it often occurs in areas where there are tensile stresses, which can lead to catastrophic failures in boiler systems. The presence of high alkalinity is typically a result of poor water management or chemical treatment in the boiler, which underscores the importance of closely monitoring and controlling the chemistry of boiler feedwater.

In contrast, while high alkalinity could contribute to other issues like foaming or corrosion under certain circumstances, it is specifically the relationship between high alkalinity and caustic embrittlement that is critical to understand in the context of boiler water chemistry management.