Coke Drum External Cracking
Coke Drum External Cracking
(OP)
Does anyone have experience with external cracking in the lower third of their coke drums? Also, how did you address or plan to address the situation?
Thanks,
John Leroux
Thanks,
John Leroux





RE: Coke Drum External Cracking
No, coke drums never crack! Ok... welcome to the forum. It's not uncommon for coke drums to crack. It is uncommom for them to get past their 5th birthday without crack.
It would help if you filled your "Personal Profile" so we would know a bit more about your background. It helps to focus our respones. Click on the "jte" at the top of this post to see my background. You'll no doubt get several responses in this forum, but also check out the "Boiler and Pressure Vessel" forum.
I'll guess that the cracks you are describing would be associated with weld seams, particularly circumferential seams. Chances are that you are looking at a situation which will progressively worsen. Consider replacing the lower 1/2 of the shell and, since you probably also have cracks in the head-skirt junction, the heads. Or just get new drums.
For a more detailed evaluation, I'd throw some money at one or more of the following outfits:
http://
http://
http://www.equityeng.com/client/pet-refining.html
http://w
jt
RE: Coke Drum External Cracking
RE: Coke Drum External Cracking
My original post was lacking some information.
We have two Cr-½Mo Coke drums that were installed in 1979. External cracking in the bottom section of the drums were removed by grinding/weld repair, however PWHT resulted in new cracks. These new cracks were removed without weld repair. At the next outage, the cracking returned, with the same grind/weld/PWHT/crack removal sequence.
I am considering two options for the future of our Coke drums.
1. Replace the bottom 1/3 of the drums.
2. Replace the drums completely.
Obviously, cost is the main driver for considering option 1. I know that many refineries have replaced Coke drums due to cracking/bulging in the past 10 years.
I would like to know if anyone has replaced the bottom section of the drum and what sort of issues did they encounter (additional cracking above the new section, need to replace top section after a period of time, etc.). Alternatively, it would be helpful if anyone has a good reason to stay away from a partial replacement.
I appreciate any help that the group can provide.
Thanks,
John Leroux
RE: Coke Drum External Cracking
RE: Coke Drum External Cracking
That type of information helps since I am looking for industry experience.
Thanks,
John
RE: Coke Drum External Cracking
Replacing the lower sections of drums has been done sucessfully in at least two refineries that I'm aware of. See the CB&I link in my previous post for more info and I'm sure they'd be happy to provide a reference list. Call the references. They may be competitors, but I've found that even competitors are willing to provide general details about jobs they've done with specific contractors. (And, no, I won't be on CB&I's reference list!)
jt
RE: Coke Drum External Cracking