Damage assessment and maintenance strategy of hydrogen reformer furnace tubes

The states of damage along a reformer tube in service for 10 years are metallographically analyzed. Damage levels are ranked relating to remaining life. The damage distribution is obtained for the whole reformer tube. The results show that the accumulated damage of the tube is non-uniform. The damage level in the lower part of the reformer tube is significantly higher than that in the upper part, especially in the weld region. The damage localization is also verified by use of a continuum damage mechanics finite element technique. Accordingly it is proposed that local replacement might be a desirable method to extend the service life when the lower part of the reformer tube reaches the safe rupture life, (C) 1999 Elsevier Science Ltd. All rights reserved.