Structural Characterization of a Coke Drum

A set of Delayed Coker Drums were placed in service in 1968, and now have 27 years of service in what may be the most violent and severe cyclic loading conditions of any petrochemical vessel. As part of the continuous evaluations of their integrity, surface contour measurements were performed to document the growth of the bulges.

Characterization by Analysis

Vessel wall contours provided by a laser based inspection profiler were digitized and input to a series of finite element models of the 201-B drum. In the ambient bulged condition, the drum is a corrugated cylinder. This creates additional stress under all loading conditions. As a simplification one particular profile was used, one that appeared to provide the largest relative distortion.