In-service induced damage assessment of Reformer Feed Heater tubes in Continuous Catalytic Reforming Unit (CCRU)

Failure analysis of Reformer Feed Heater tubes in Continuous Catalytic Reforming Unit (CCRU) - A case study *Shekhar Roy, *Q.M.Amir , * S.P.Dubey , **P.Deshmukh and ***A.K.Lahiri *Indian Oil Corporation Limited, R&D Centre, Faridabad, India royshekhar@iocrd.co.in, amirqm@iocrd.co.in ***Corrosion Materials and Inspection Consultant, New Delhi, India lahiri04k@rediffmail.com ABSTRACT Substantial loss in thickness from inside in the charge (first) heater in the outlet end was observed.Subsequently pinhole leakage occurred in the first charge heater causing shutdown of the unit. Heater tube samples collected from all three heaters confirmed carburization of tubes after studies. This carburization mechanism has been experienced for the first time in CCRU unit. Depending on the location; carburization was found to be negligible, partly and thru & thru. The cause of carburization and failure has been attributed to increased throughput from the furnace, higher tube temperature, injection of Tri-Chloro Ethene (TCE) and cracking of aromatic hydro carbon. This active carbon at higher temperature diffuses readily in steel causing carburization of the tubes from inner side across the thickness. The present paper will describe the detailed discussions on investigation of carburization and material failure. KEY WORDS: Coke, Ultrasonic, 5 Cr ½ Mo, Carburization, Tri-Chloro Ethane