×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Etan Cracking furnace tubes failure
2

Etan Cracking furnace tubes failure

Etan Cracking furnace tubes failure

(OP)
Hello Dear Experts,

1. In April-2017, Etan Cracking furnace tubes, U elbows and hanger supports were completely renewed as planned.
2. On August-2019, the furnace was stopped to decoke. As a result of the inspection activities, the magnetization results were found to be normal and the percent of carburization was 22% (below 50% limit).
3. However, the tubes with out-of-limit bulge limit have been replaced by new tubes and with relatively good retention tubes from previous years.
4. On 11.11.2019, during the replacement of the flat tubes, serious cracks were detected in the inspection of all three upper U-bends that were cut up to that time.


What is your thoughts and recommendations?

RE: Etan Cracking furnace tubes failure

My recommendation: engage the services of a expert in the subject. This is far more than can be accomplished, for free, over the anonymous internet.

RE: Etan Cracking furnace tubes failure

Dear erkuts,

1. Gather all the Operational records from DCS / PLC regarding temperature of the tubes.

2. Ensure that temperature of the tubes is monitored at least once in a shift with portable IR gun and matched with the thermocouples.

Poor operation and instrumentation (like improper thermocouple locations / improper thermocouples / temperature not reaching the DCS / PLC) are common causes for such failures.

Regards.

DHURJATI SEN
Kolkata, India

RE: Etan Cracking furnace tubes failure

(OP)
Thank you

RE: Etan Cracking furnace tubes failure

I suspect that there is a design weakness that may need some design modifications where the "U" bands are located. Two probable causes come to mind. First the expansion of the tubes may be restricted at supports while the tubes are cold and then get heated resulting in undue stress at welds; frequent start ups during a workday would be problematic to the welded connections at the tube supports during the heating and cooling cycles. Secondly look at the "U" bands for thinning of their wall thicknesses due to corrosion. Lastly remove damaged sections and have them microscopically examined by a metallurgist for an evaluation. You should also provide the metallurgist a sketch or diagram of the tube arrangements with all flow paths indicated for his or her benefit.

RE: Etan Cracking furnace tubes failure

TGS4:
I've said that myself many times here, but not as concisely as that.

Chicopee:
After a single sentence based on a 'suspicion', without material in hand, without NDE data or detailed history you are launching into 'probable causes'. Please refrain.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Etan Cracking furnace tubes failure

Let me explain the reason for my statements. One of my accounts had an economizer with about 60 "U" tubes most of which had cracked. These "U" tubes were supported by welded plates anchored to the economizer main frame. The cracked joints were the result of the rigid connections unable to cope with the expansion and contraction during the operation of the boiler. Furthermore, in my reply, I indicated that a metallurgist evaluate the cause of the OP's problem since obviously where we stand there is no way to verify the information that we were provided. So the OP's problem appears similar to the fate of my account so my reply is all conjecture.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

White Paper - PLM and ERP: Their Respective Roles in Modern Manufacturing
Leading manufacturers are aligning their people, processes, and tools from initial product ideation through to field service. They do so by providing access to product and enterprise data in the context of each person’s domain expertise. However, it can be complicated and costly to unite engineering with the factory and supply chain. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close