Khaled Sadek, Ph.D., P.Eng. - Suncor
Cokers equipped with dual inlet feed have been reported to leak frequently at the joint connection with the Bottom Un-heading Device (BUD) leading to a series of unplanned outages & a large loss in production.
In this study a three dimensional (3D) non‐linear structural finite element analysis (FEA) model was developed to investigate the root cause of the connection failure. Thermography was conducted on the dual inlet cone and joint connection for the full 12 hour coking cycle. Temperature data from the thermography was used as an input load to the FEA model.
The study proves that hot spots generated from the dual inlet feed and the temperature gradient across the dual inlet cone circumference are the main contributors to the flange warpage leading to the connection failure due to the uneven gasket stress distribution. Different scenarios for gasket face out of flatness were also modeled and a criterion for gasket face machining that exceeds ASME PCC‐1 was developed in this study. Applying the developed criterion proved success in stopping the leakage that was experienced at the Coker‐BUD connection.