What is the function of a deaerator?

• A. It uses stripping steam to remove and dissolve oxygen from boiler feed water before it enters the boiler
• B. It filters impurities from feedwater
• C. It heats feedwater to boiling
• D. It stores feedwater temporarily

Answer: (A)

Removing dissolved gases from boiler feedwater to prevent corrosion is what a deaerator does. It uses stripping steam to remove dissolved oxygen (and carbon dioxide) from the feedwater before it enters the boiler. This reduces the risk of oxidization and corrosion inside the boiler tubes, which helps extend equipment life and efficiency. The stripped gases are vented while the water is heated toward boiler temperature, improving gas release. Among the options, this description best captures the deaerator’s function: using stripping steam to remove gases from feedwater before it enters the boiler. The other choices describe filtering, heating to boiling, or storing water, which are not the primary purpose of a deaerator.