Online Continuous Corrosion Monitoring for Detection, Monitoring and Control of Localized Corrosion

Abstract Non-intrusive continuous wall thickness monitoring systems are fast becoming industry best practice for online detection and monitoring of corrosion and erosion. Challenges with localized corrosion have been knowing where to deploy online monitoring sensors and also being able to quickly and easily interpret the data that is delivered. The authors will demonstrate that deploying only a modest number of point measurement devices in an area of elevated localized corrosion risk will provide the best possible combination of probability of detection (POD) as well as ongoing wall thickness monitoring for localized corrosion attack. Recent advances in ultrasonic signal processing that takes advantage of specific historic data that is recorded by the online wireless wall-thickness monitoring system has been instrumental in separating the effects of wall-thickness loss from changes to internal surface morphology at the measurement locations. These advances make the data from the online monitoring system considerably easier to understand and interpret when the corrosion mechanism that is occurring is creating a rough internal surface at the measurement location – i.e., as per many localized corrosion mechanisms. Specific field examples from the ~10,000 installed sensors worldwide are presented to demonstrate the improvements of the new signal processing technique.