Troubleshooting. Corrosion of high-nickel stainless steel plates was found to occur in a d...

Troubleshooting. Corrosion of high-nickel stainless steel plates was found to occur in a distillation column used at DuPont to separate HCN and water. Sulfuric acid is always added at the top of the column to prevent polymerization of HCN. Water collects at the bottom of the column and HCN at the top. The amount of corrosion on each tray is shown in Figure P3-5B as a function of plate location in the column.

The bottom-most temperature of the column is approximately 125 °C and the topmost is 100 °C. The corrosion rate is a function of temperature and the concentration of an HCN-H2S04 complex. Suggest an explanation for the observed corrosion plate profile in the column. What effect would the column operating conditions have on the corrosion profile?