The development of techniques to detect high temperature hydrogen attack – A mini review

Abstract

High temperature hydrogen attack (HTHA) is classified as one of the problematic failure mechanisms which normally occurs in petrochemical refineries. It causes degradation in a material due to high temperatures and pressures that are involved. Carbon steel and low alloy steels are the materials that are most prone to this damage mechanism. The main challenge facing refineries is the early warning systems that can be used to detect this failure before it is at an advanced stage. Due to the challenges of HTHA inspection, several advanced non-destructive examination techniques have been developed over the years. This includes acoustic emission testing (AET), automated ultrasonic detection and classification (AUDC), and more, where many of these techniques are microstructural based. Although there have been several new developments for detecting this failure mechanism, some developments are more focused on continuous monitoring of material behaviour under operational conditions. However, most techniques being used are normally deployed to detect all possible material failures including corrosion. These techniques can’t be used as a stand-alone for HTHA detection due to complexity and the nature of data. This paper briefly reviews the techniques that have been developed to detect HTHA. The detection accuracy of the systems being developed, and the level of implementation are also discussed. The techniques used to track the sites of hydrogen in metals are also reviewed with the purpose of establishing whether those techniques can be used in monitoring the HTHA. This will assist in understanding the gaps around HTHA detection.