Probing and separating corrosion and erosion of pipeline steel using electrical resistance method in conjunction with electrochemical measurements

A specially designed erosion-corrosion sensor system which combined the electrical resistance (ER) and electrochemical impedance spectroscopy (EIS) measurements was established to on-line probe and separate the corrosion component and erosion component from the total metal loss. The measurement accuracy of the sensor system for both corrosion and erosion under different flow conditions was experimentally studied. Results show that the occurrence of localized corrosion would not influence the accuracy of the EIS measurement under active corrosion. The ER method could accurately probe the degradation of the carbon steel under uniform corrosion. However, the measurement error of ER method could not be neglected when localized erosion-corrosion occurred at high flow rate conditions. A methodology was proposed to reduce the measurement error of ER method using electrical field simulations and local 3D profiles characterization. On the basis of the newly developed sensor system, the initiation and propagation of erosion-corrosion could be well monitored.

Automated summary

By combining resistance and electrochemical impedance measurements, the specially designed erosion-corrosion sensor system can accurately monitor and distinguish between corrosion and erosion, accurately detecting the degradation of carbon steel while proposing methods to reduce measurement errors.