Damage assessment and maintenance strategy ofhydrogen reformer furnace tubes

The states of damage along a reformer tube in service for 10 years aremetallographically analyzed. Damage levels are ranked relating to remaining life. The damagedistribution is obtained for the whole reformer tube. The results show that the accumulateddamage of the tube is non-uniform. The damage level in the lower part of the reformer tube issignificantly higher than that in the upper part, especially in the weld region. The damagelocalization 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 theservice life when the lower part of the reformer tube reaches the safe rupture life.