Investigation of probable cause of damage of steam drum of naphtha cracking furnace

This investigation was primarily aimed to examine the probable causes of damage in steam drum of heat recovery boiler in a naphtha cracking plant. Large number of cracks was detected of varying length on the inner surface of the drums. Preliminary visual examination, magnetic particle inspection, in situ metallographic examinations were carried out at the site. Detailed optical microscopic analysis along with scanning electron microscopic (SEM) and transmission electron microscopic (TEM) examinations on the scooped samples from different locations of the steam drum were carried out to understand the metallurgical reasons for damage. Stress analysis was carried out on the steam drum on the basis of strength for the internal pressure. Finally, it was concluded that metallurgical factors as well as operating conditions were responsible for the cause of damage in the steam drum.