Sodium Sulfite as Oxygen Scavenger
The dosage of sodium sulfite or other oxygen scavengers may be calculated by looking at their reaction rate to remove the oxygen and then their residual dosage to provide a feedwater or boiler water residual.
Sodium Sulfite Example
The reaction rate is:
2Na2SO3 (7.88 ppm) + O2 ( 1 ppm) → 2Na2SO4
For the residual, 1.6 ppm Na2SO3 will yield 1 ppm SO3.
The total calculation equation to remove residual oxygen and provide a boiler water residual is: