Which type of corrosion is likely to affect the upper shell and top head of a distillation tower?

Chloride attack is especially relevant in environments such as distillation towers, where chloride ions are present. This form of corrosion often manifests at elevated temperatures and can lead to localized pitting or stress corrosion cracking in susceptible materials. The upper shell and top head of a distillation tower are typically exposed to conditions that can enhance the likelihood of chloride-induced damage, including the presence of water vapor, high temperatures, and concentrated chloride solutions.

In a distillation tower, as the process involves the distillation of various compounds, volatile components can carry chlorides into the upper sections of the tower. This creates a conducive environment for chloride attack, which can become quite severe due to the specific environmental factors present in those upper areas.

While other forms of corrosion, such as galvanic, crevice, and uniform corrosion, may also affect pressure vessels, they do not have as direct or significant an impact on the upper shell and top head of a distillation tower in the same way that chloride attack does under the discussed conditions. Advanced understanding of the specific threats posed by chlorides can help in implementing appropriate materials and protective measures to mitigate corrosion, ensuring the longevity and structural integrity of pressure vessels.