What is condensate polishing and why is it used?

• A. A method to filter condensate for particulates.
• B. A treatment to remove dissolved impurities from condensate (ion exchange or polishing beds) to protect boiler and turbine metals and improve feedwater quality.
• C. A process to heat condensate.
• D. A method to acidify condensate.

Answer: (B)

Condensate polishing is the final treatment of condensate water in the steam cycle to remove dissolved ionic impurities using ion-exchange polishing beds (cation and anion, often in a mixed-bed setup). After steam condenses, the water returns as condensate, and if it carries dissolved minerals, those contaminants can cause corrosion and deposits in boiler tubes and turbine components and degrade feedwater quality. The polishing process exchanges unwanted ions for harmless ones, producing very low-conductivity, high-purity water that protects metals, reduces corrosion risk, and improves heat-transfer efficiency in the boiler and turbine. It’s about removing dissolved impurities, not just filtering particulates, heating, or acidifying the condensate.