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The Monitoring of the Erosion and Corrosion Using Electrical Resistance Sensor Combined with Electrochemical Method

Paper Number: 43
Author/s: Liang Liu1, Yi Huang1, Yunze Xu1, Xiaona Wang2 & Shide Song3
Organisation: 1School of Naval Architecture Dalian University of Technology, Liaoning Province, China 2School of Physics Dalian University of Technology, Liaoning Province, China 3School of Civil Engineering Dalian University of Technology, Liaoning Province, China

It’s well known that when the steel suffers erosion-corrosion in a flow dynamic condition, the total material loss rate (Vt) of the steel consists two components, i.e. the corrosion part Vc and erosion part Ve. The corrosion rate can be on-line monitored using traditional electrochemical methods. However, the erosion part only can be separated after the whole test duration through weight loss measurement. The dynamic vibration of the erosion rate cannot be obtained for energy pipelines. In this work, a novel designed ER-EIS sensor system was developed to separate the Vc and Ve using electrical resistance (ER) method in combination with electrochemistry impedance spectroscopy (EIS) measurement. The Vt could be monitored by ER method and the Vc was detected by EIS measurement. Therefore, Ve can be easily obtained through the difference of Vt and Vc. A flow loop used for simulating the erosion-corrosion working condition was established to test the sensor system. The erosion-corrosion was studied under the 4 m/s flow rate in the pure fluid condition without sand particles and in the sand containing slurry, respectively. The erosion-corrosion was on-line studied using the sensor system and the surface morphologies in two different pipeline working conditions were observed using microscope. The ER measurement results were well matched to the weight loss of the test sample measured by gravimetric methods suggesting the high accuracy of the ER technique. The surface morphologies show that the propagation of the erosion-corrosion in two different conditions was quite different. In addition, the pure erosion was measured in the flow loop under chathodic protection. The synergy of the erosion and corrosion was possibly studied through test results.