Abstract
An electrochemical sensor for on-line corrosion monitoring in boiler condensate systems has been developed. Linear polarization was used with a three-electrode electrochemical probe to determine the polarization resistance and the corrosion rate. An ionically conductive film was placed between the reference and the working electrodes to reduce the apparent solution resistance. Without this conductive film the corrosion rate will be underestimated in low-conductivity media because of the high solution resistance. Compared to other techniques, such as electrochemical impedance spectroscopy, this sensor provides a simple, low-cost alternative to measure corrosion in low conductivity water.
The sensor can be made as a portable unit or as a permanently installed system for continuous on-line corrosion monitoring in plant steam/condensate systems to evaluate the performance of various water treatment programs. Preliminary laboratory and field studies showed that this sensor was capable of measuring the corrosion rate in low-conductivity condensate. The effects of variations in temperature, dissolved oxygen concentration, pH, and metallurgy on corrosion rate data obtained with this sensor in deionized water are discussed.
