The Significance of Coke Resistance in Coke Drum Failures

Shell bulging and cracking in coke drums have been documented for decades. Most of the literature on the subject attributes these failures to severe spatial and temporal thermal gradients that develop during the quench part of the operating cycle. While transient thermal gradients can be severe and can cause excessive stresses, they alone cannot explain all types of observed shell damage in drums. In this paper, the authors present and discuss observations that suggest that when a cooling shell contracts during quenching, the interaction of the cooling shell with the in-situ coke in the drum can induce substantial hoop and axial stresses in its wall. The manner and degree to which this resistance plays a role in causing damage appears to depend on the type of coke produced and the way drums are operated.