Crude Distillation HCl Corrosion – Understanding Water Dew Point vs. Salt Point vs. Ionic Dew Point

The understanding of the causes of corrosion in the overhead of a refinery crude oil distilling unit has been evolving rapidly over the past decade. The industry has evolved over time from recognizing corrosion due to HCl, with the worst corrosion concentrating at the Water Dew Point, then to discovery of Salt Point at a higher temperature, then to calculations of an Ionic Dew Point at an even higher temperature. Most recently the capability has been expanded to calculate all three of these key points simultaneously, and further expanded to consider multiple acids and amines at the same time. This presentation will focus on the latest capability, presenting data and calculations for specific units and showing the impact of variable process conditions and contaminants on corrosion risk.