Structural Characterization of a Coke Drum

Part 1

By Richard S. Boswell, P.E. at Stress Engineering Services, Inc., and Tom Farraro at CITGO Petroleum Corp. This article appears in the March/April 1996 issue of Inspectioneering Journal.

1 Like

0 Comments

Topics

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...
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...
Results of a Successful Risk Based Inspection Study: Oil Stabilizer Facility

March/April 2011 Inspectioneering Journal

Due to increasing market demands for stabilized crude, it is a high priority for oil handling and processing facilities to avoid production interruption. One optimization opportunity is to review our approach for scheduled facility Test and...

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 VII/Div 1 pressure vessel design based on 60 psi and 836 0 F at the top and 899 0 F at the bottom. This design provides increasing thickness, from the bottom up, in seven rings constructed with clad plates, using longitudinal and circumferential weld seams.

The drums were instrumented in June 1993 with 40 thermocouples and six strain gages to characterize their structural behavior for an extended recording period. The results were sufficient to justify leaving the instrumentation in place to record every cycle of operation. After the first year, the thermocouples were moved to different locations around the drum and eventually reduced to only the three strain gage locations. This performance history was an integral component of the evaluation concluded in May of 1995 resulting in the replacement of significant portions of the drums because of distortion. The instrumentation is currently monitoring the companion pair of drums.