An inspection of coke drum repair procedures leads to big savings

A coke drum mechanical integrity solution produces efficiencies in repair procedures and cost savings in reduced repair time.

Client: International refinery operator, North America
Asset type: Coke drums in a refinery
Key issue:Cracks in coke drums and costly repair time procedures neededimprovement.

Business challenge for the client

Under normal working conditions, a coke drum experiences high pressure and high temperatures resulting in small cracks occurring over time. These cracks require operators to shut down their facility to perform maintenance. This downtime can have a measurable cost in the 100s of thousands of dollars. A leading Midwest refinery operator invited Lloyd’s Register into their facility to evaluate their current coke drum repair procedures with the goal of reducing repair time. During an on-site evaluation,our consultants developed a new repair procedure that allowed the operator to reduce their shutdown time by 13 days. This single event saved the operator more than $10 million.

How we helped

The value that we provided the operator did not stop at developing the repair procedure that they use during a shutdown.

We also developed an on-line inspection and repair procedure which resulted in the discovery of an eight inch coke drum crack. The crack was repaired on-line enabling the facility to cancel the next two-week shutdown. With the inspection and repair procedure now implemented, the operator estimates that they avoided three additional shutdowns and saved an estimated $15 million.

After the initial inspection and repair, a comprehensive, real-time monitoring program was initiated to monitor stresses and temperatures on coke drums. The data gathered using strain gages and thermocouples during operations will be used to correlate with changes in process variables.

From these results, we will guided the operator in making changes to the preheating and quenching procedures in order to decrease localised thermal stresses on the shell and skirt. This will minimise the likelihood of coke drum cracking and result in further savings.

Results and benefits

To date, the facility has saved more than $25 million and we were able to deliver the current and anticipated future savings by developing new and more effective repair procedures, recommending operational changes to reduce cracking, and by implementing monitoring to capture and understand how the ever-changing facility operations are impacting the coke drum and what can be done to minimise cracking.