Condensate Treatment

When the steam leaves the boiler, the water treatment program’s job is still not done. When the steam has completed its work of heating a process, product or space, it condenses back into liquid water called condensate. In most systems, the condensate is collected in condensate receivers, from where it is returned to the boiler room and reused to make more steam.

Two types of condensate return treatments are available – neutralizing amines and filming amines. Of the two types, by far the most commonly used are the neutralizing amines, which are volatile alkaline liquids. A neutralizing amine is fed to the boiler, where it volatilizes and is carried off with the steam. It can also be injected into the steam line exiting the boiler. When the steam condenses, the neutralizing amine dissolves in the condensate, and, being alkaline, raises the condensate pH. Neutralizing amines are fed at a dosage rate sufficient to raise the condensate pH into the 8.0 to 9.0 range, protecting the condensate system from acidic corrosion.

Filming amines are only slightly soluble, and thus cannot be fed into the boiler. They must be injected directly into the steam line using a specially-designed injection nozzle that atomizes the amine into the steam. When the steam condenses, the filming amine coats the condensate piping with a waxy molecule-thin film. The film prevents contact of the acidic condensate with the condensate system metal, thus preventing corrosion of condensate receivers, pumps and piping. Filming amines protect condensate piping against both acidic and oxygen corrosion, but are more difficult to feed and control than neutralizing amines.