The Effect of Hydrazine Addition for the Behavior of Flow Accelerated Corrosion under the Oxidizing Environment

Abstract

An all volatile treatment (oxidizing) (AVT (O)) is expected as countermeasures against flow accelerated corrosion (FAC) of carbon steel piping at a power plant. Dissolved oxygen (DO) in the feed water inhibits FACs while DO can cause local corrosions at high temperature. A hydrazine (N₂H₄) eliminates DO at high temperature. We discussed the FAC mitigation effect of AVT (O+N₂H₄) where N₂H₄ was added to the feed water under AVT (O) condition. From the corrosion test of carbon steel pipes in NH₃ solution at 150 ℃ under the high flow rate condition, FAC inhibition effect of DO at 15 μg/L is indicated in the presence of N₂H₄.