Failure of package boilers in a petrochemical plant

The paper deals with the failure investigation of furnace‐tubes of a few medium capacity (86 T/H steam generation) package boilers in a petrochemical plant. As a consequence of damage, the boilers required major tube‐repair on urgent basis, and complete tube replacement within a period of two years. Failure of different boilers took place at varying service durations, though all of them had the same design and criteria of operation. The study included metallurgical characterization of the failed components; analysis of operation and process (historical) data; review of inspection and maintenance records; evaluation of design and water‐treatment practices; etc. As a result, water‐side corrosion was attributed to be the cause of tube‐leakage via general and localized corrosion mechanism, while, no metallurgical defects and changes were noticed in the failed components. On the other hand, process and operational abnormalities were diagnosed as the root cause of trouble initiation and propagation. In order to avoid the recurrence of such failures, various preventive measures (inspection, maintenance, operation and process) have been recommended.