Session: DA-15-01 8th International Symposium on Coke Drum Life Cycle Management 1-Coke Drum Skirt Integrity

Paper Number: 123402

123402 - Coke Drum Skirt Life-Cycle Management 

Delayed coking is a form of thermal cracking used for processing “bottom barrel” residuum, and Coke drums are the heart of the delayed coking process.  Cyclic and aggressive operating conditions require special considerations to manage the mechanical integrity of these vessels because they are subjected to severe thermal cycling with the skirt to shell connection weld being vulnerable to fatigue cracking.  The special considerations should be considered through the life-cycle of the coke drum.  In this paper, key aspects of coke drum life-cycle management will be discussed, covering the useful life of these vessels from “cradle” to “grave”. Important aspects such as supplemental requirements for design and fabrication, specialized in-service inspection, on-line monitoring, engineering assessment tools, repairs and replacements will be covered in detail.  This paper includes a short literature review of common skirt designs and damage mechanisms of greatest concern with consideration given to fabrication of skirts for both new coke drums and skirt retrofitting projects.  Five case studies are reviewed in detail including: the analysis of the skirt configuration for a new pair of coke drums; a coke drum set skirt retrofitting project; two skirt repairs event in two separate coke drum sets; on-line monitoring project of a coke drum skirt using a health monitoring system.  The paper will include closing remarks and recommendations to help improve the management of skirts for these complex and critical pressure vessels.

Presenting Author: Antonio Seijas P66

Presenting Author Biography: Antonio has more years of experience in the oil industry and joined Phillips 66 in 2010, serving as corporate Fixed Equipment Engineering Lead and providing technical support to refining, midstream, and projects. He has is a BS in Mechanical Engineering, a MEng on Materials, and a MSc in Welding Engineering. Antonio is member of several ASME committees and API task group, including the ASME/API Joint Committee on Fitness-For-Service, ASME PCC-2 (repairs), API 934 TG G and J (coke drums), etc. He has been supporting the ASME PVP D&A Technical Committee in recent years with the organization of the International Symposium on Coke Drum Life Management.

Authors:

Antonio Seijas P66
Alex Berry Phillips 66 Limited