Where is pitting corrosion most commonly observed in a boiler system?

Pitting corrosion is most commonly observed inside the steam drum and feedwater injection pipe of a boiler system due to the conditions that promote localized corrosion. In these areas, the presence of water, oxygen, and fluctuating temperatures creates an environment where small, deep pits can form as a result of the chemical and electrochemical reactions taking place.

The steam drum, which operates at high temperatures and pressures, provides an ideal environment for pitting due to the accumulation of impurities and dissolved solids. When feedwater is injected, it often contains contaminants that can settle and create localized concentrations, leading to pitting. Additionally, the temperature and pressure variations inside the drum can contribute to the instability of the protective oxide layer on the metal surface, further enhancing the potential for pitting corrosion.

Understanding the dynamics of flow, temperature changes, and chemical concentrations in these critical areas is essential to managing and mitigating the risks of pitting, thereby ensuring the longevity and reliability of the boiler system.