Reliability of Coke Drums

Part 1

By Eivind Johnsen at DNV Inc., Lynne Kaley, Director of Reliability Strategy at Pinnacle, and Andy Tallin at DNV Inc. This article appears in the November/December 1996 issue of Inspectioneering Journal.

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Topics

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Reliability of Coke Drums

January/February 1997 Inspectioneering Journal

This is Part II of a series of reliability of coke drums. Part I discussed some of the causes of bulging and cracking in coke drums. Here, the effect of operation on damage will be covered, along with possible solutions for increasing drum life...
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March/April 1996 Inspectioneering Journal

A pair of delayed coker drums was placed in service in 1968, and now have 28 years of service in what may be the most severe cyclic loading conditions of any petrochemical vessels. They are a conventional ASME VIII/Div 1 pressure vessel design...
Enhanced Fitness for Service Evaluations

November/December 1995 Inspectioneering Journal

Evaluations of aged and critical service vessels such as FCCU's and Delayed Cokers have been aided by the addition of two physical measurements referred to as structural characterizations. These are placed in perspective with the classic...
Stress Assisted Corrosion and Fitness for Service in 66 Year Old Boilers

September/October 2014 Inspectioneering Journal

Maintaining mechanical integrity for aging power boilers can be challenging. This article provides a case study on how mitigating one damage mechanism led to the discovery of another, and how refinery engineers collaborated with industry experts to...
Remote Internal Inspection of Coke Drums

July/August 1995 Inspectioneering Journal

Delayed coker vessels experience severe loading sequences as they are routinely filled with hot liquid product (approx. 9000 F) and quenched to ambient temperature in a relatively short time period. The industry trend is to shorten the operating...

This article is part one of a 2-part series on Coke Drum Reliability.

Part 1| Part 2

Petroleum coke production is an important source of revenue for many refineries. While coking units were initially constructed to deal with a waste product, these units are now of significant economic value.

Worldwide, an estimated 3.8 million barrels of petroleum coke are produced per day. Figure 1 shows the distribution of coke production; nearly 50% of the production is concentrated in the US. Delayed coking is the most common coking process, accounting for as much 3.3 MMbpd.

Figure 1- Coking capacity worldwide — Figure 1. Coking capacity worldwide

Coke drums are an essential component in the delayed coking process. These drums are used to separate petroleum coke from lighter hydrocarbons. Many drums have reliability problems. Because the drums are central to the coking process, poor drum reliability can lead to frequent shutdowns and low productivity.

Coke drums are constructed of a vertical cylindrical shell with an elliptical top and a conical bottom. They range from 60' to 80' in height and 15' to 30' in diameter. Skirts, attached near the shell to cone weld area, are used to support the drums. Most coke drums are made of C-1/2 Mo or Cr-Mo steel and internally clad with stainless steel.

Operation

In delayed coking, coke drums are operated in pairs where only one drum is filled at a time. Coking cycles, from fill start to fill start, last between 24 and 48 hours.

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About the Authors

Eivind Johnsen at DNV Inc.

Lynne Kaley, Director of Reliability Strategy at Pinnacle

Lynne Kaley, Director of Reliability Strategy at Pinnacle, has over 30 years of refining, petrochemical, and midstream gas processing experience. Lynne was an owner/user plant metallurgist/corrosion and corporate engineer for over 10 years and has 20+ years consulting with plant management, engineering, and inspection departments, including Risk-Based technology (RBI) development leader, the... Read more »

Andy Tallin at DNV Inc.