Oxygen scavenger
Oxygen scavenger turns up in 2 fields: corrosion, boilers. Here is what it means to the people in each one.
Oxygen scavenger in corrosion
Chemical that strips dissolved oxygen from water to stop oxygen pitting in boilers and injection systems.
An additive that reacts with dissolved oxygen so it cannot attack steel. Sodium sulfite and bisulfite are standard in low-pressure boilers and seawater injection, while hydrazine, carbohydrazide and DEHA serve higher-pressure boilers. Even traces of oxygen drive severe pitting in hot water systems, so scavengers back up mechanical deaeration, with residuals checked every day.
"Sulfite residual's at zero on the boiler feed, the oxygen scavenger pump lost prime overnight."
Oxygen scavenger in boilers
A chemical fed to boiler feedwater that reacts with and removes the last traces of dissolved oxygen.
Sodium sulfite, often catalyzed to react faster, is the standard choice in low and medium pressure boilers, and operators test for a sulfite residual to prove enough is present, commonly in the 20 to 40 ppm range. Higher pressure plants use volatile scavengers such as carbohydrazide or DEHA that add no solids. The scavenger finishes what the deaerator starts; it is not a substitute for one.
"Sulfite residual's zero on the morning test, the scavenger pump lost prime, get it fed before the oxygen gets a foothold."