Portable Eddy Current Inspection System with Real-Time SVM Classification of the Aging States of Steam Reforming Furnace Tubes

Abstract

The petrochemical industry heavily relies on steam reforming furnaces for large-scale hydrogen production. Centrifugally cast HP stainless-steel tubes constitute the majority of components in these furnaces, enduring temperatures ranging from 600 to 1000 ºC for extended periods. These tubes manifest distinct aging states, characterized by specific microstructural markers linked to the exposed wall temperature. Given their significant cost and importance, monitoring the service life of these tubes is crucial. The current aging state is particularly relevant due to the correlation between creep damage and advanced aging stages. Hence, this study aims to assist in assessing the remaining life of HP stainless-steel tubes by employing a portable Eddy Current Testing (ECT) inspection system, coupled with real-time Support Vector Machine (SVM) classification of aging states. Two 12.6-meter-long tubes, aged for 160,000 hours, underwent inspection using the portable ECT inspection system to evaluate the progression of aging states along their height, considering the expected vertical temperature gradient. Results underscore the efficacy of the SVM classification in identifying the various aging states present along the studied tubes, highlighting promising in situ applications.