Application of flexible resistometric sensors for real-time corrosion monitoring under insulation

Corrosion under insulation (CUI) is a form of corrosion typically occurring on steel pipes and vessels covered with thermal insulation. CUI is a critical issue in petrochemical and refining industry leading to significant financial losses and severe environmental hazards. State-of-the art CUI monitoring system consisting of wireless loggers with flexible resistometric sensors is used to assess the effect of insulation material, position, and presence of a defect on the actual corrosivity toward carbon steel under alternating condensation conditions. All three considered factors together with the climatic parameters and presence of corrosion products are important for the CUI process. Most complex is the role of the insulation material as the properties inhibiting corrosion under intact insulation may be linked to a worse insulating ability. Because of the high sensitivity and immediate response of the sensors, the technique can be applied for timely CUI detection of insulated pipelines in both industrial facilities and laboratory studies. The paper presents a state-of-the-art system to monitor corrosion under insulation (CUI). The system consists of flexible sensors, wireless loggers, and a web interface that allows actual corrosivity evaluation and timely CUI detection in both laboratory and real industrial facilities. High sensitivity and immediate response of the sensors were used in the study to evaluate the effect of climatic conditions, insulation material, and defect presence in the insulation on corrosion rate of carbon steel piping.image