The most often encountered condensate system corrosion in boilers is caused by carbon dioxide
- The dissolved gases normally present in water cause many corrosion problems. Carbon dioxide exists in aqueous solutions and as the combine forms of carbonate and bicarbonate ions.
- Carbon dioxide dissolves in water & produces corrosive carbonic acid. The low pH resulting from this reaction a enhances the corrosive effect of oxygen. CO2 + H2O ——> H2CO3
- Heating the feed water and maintaining it at a high temperature prior to its delivery to the boiler can drive off carbon dioxide.