New York Low Pressure Boiler COF Practice

Which chemical is suitable for oxygen scavenging in a boiler?

1. Calcium Carbonate

2. Sodium Chloride

3. Sodium Sulfite or Sodium Hydroxide

4. Potassium Nitrate

The correct answer is: Sodium Sulfite or Sodium Hydroxide

The use of sodium sulfite or sodium hydroxide as oxygen scavengers in a boiler is essential for preventing corrosion. Oxygen in the boiler water can lead to significant damage, particularly to the metal components, resulting in increased maintenance costs and operational failures. Sodium sulfite is a commonly used oxygen scavenger because it reacts with dissolved oxygen to form sodium sulfate, effectively removing free oxygen from the water. This process helps protect the boiler's internal surfaces from oxidization, thus enhancing the overall longevity and efficiency of the boiler system. Sodium hydroxide, while primarily used to control pH, can also play a role in reducing oxygen's corrosive effects in specific applications. In contrast, calcium carbonate mainly functions as a scale-forming compound and does not effectively scavenge oxygen. Sodium chloride is used for various purposes, including water softening, but it does not serve the function of oxygen scavenging. Potassium nitrate is a nitrate compound that can help with other processes in boiler water treatment but is not classified as a standard oxygen scavenger. Thus, sodium sulfite and sodium hydroxide are the appropriate chemicals for oxygen scavenging in boiler operations, making this choice the most suitable.