A New Method for Corrosion Prevention

The Dangers of Chloride and Sulfate

Power plants continuously face corrosion caused by chloride and sulfate under high pressure water and steam conditions. Pitting, stress corrosion cracking and other forms of corrosion attack boiler and steam generator tubes, turbines and other key components in the steam-water cycle. Deposited corrosion causes additional losses through under-deposit corrosion, lowered efficiency and more frequent shutdowns for cleaning.




As a result, monitoring of chloride and sulfate at very low ppb limits is being specified as part of cycle chemistry guidelines and turbine warranty requirements.

Existing Measurement Technologies Have Their Problems

Demonstrating compliance with these limits has been a challenge for power plants. With a lack of practical on-line measurement technologies, cycle chemistry guidelines have relied on inferred measurements such as cation and degassed cation conductivity. These are important techniques for monitoring water purity during startup, but do not quantify the concentration of chloride and sulfate ions.

Ion Chromatograph and Inductively Coupled Plasma technology provide the separation and sensitivity needed to measure chloride and sulfate at the re­quired low ppb levels. However, the cost of these instruments and the skilled person­nel required for their operation places them out of reach for most power plant budgets.