Hammering in Kettle Reboiler. (Now, the answer is here) 1

[ghamsa]

Last in April, 2004 a question was raised concerning a hammering in a kettle reboiler on the steam side. Many members such as Monetmayor, 25362, sshep, and many others helped troubleshooting this problem.

In this thread I will go through the following points:
1) thanks for all members who helped troubleshooting this problem.

2) The original thread was removed for some reason and can not be retrieved. Sorry!!!

3) The reason behind the hammering was the partition in the channel head found sheared off. This damaged partition plate allowed for steam-condensate contact which resulted in hammering.

4) I have pictures of this sheared off partition plate. Also, Monetmayor prepared excellent sketch of a well designed trouble-free reboiler should look like. If any one is interested to see the pictures and Monetmayor's work on the reboiler, please E-mail me at

trebor10@mail.com

Thanks all

 

[25362]

Now is the time to consider whay it has happened. If the reason is CO2 corrosion behind the partition plate, a more effective venting of this zone should be considered.

 

[Montemayor]

All:

This event (original thread & subsequent action) has to be recognized as one of the major success stories related to the engineering consultation and discussion carried out in this Forum. As ghamsa (a.k.a. Ahmad) has stated, I've organized the basic data, a detailed sketch and the great inspection photos revealing the cause in an excel workbook. From the six photos, I identify this process failure as caused directly by a sudden, unexpected (& undesirable) steam flow inrush into the steam bundle (probably during a process upset or a startup), causing such a strong force on the horizontal partition plate in the channel, that the plate was literally sheared off its weld joint to the channel. The photos show this dramatic result in vivid details. I've recommended an impingement plate directly below the 16" steam inlet together with an instrument "fix" of installing a "ramping" mode on the steam control valve to eliminate the future possibility of this occuring again in the future. I believe there are a total of 5 of these huge reboilers operating under these conditions.

I congratulate Ahmad for his perseverance, determination and follow-through in not only recognizing an unacceptable process problem, but more importantly in seeking out the cause and resolution rather than just turning a deaf ear and blind eye to what was obviously a bad operation taking place. I personally have never seen this mechanical failure before in the field - but I've heard of partition plate deformation(s) due to severe inlet flow direct impingement. A sudden inrush of full steam flow can, in my opinion, easily cause the traumatic effect clearly shown in the photos.

Once again, I would emphasize the successful results that this type of Forum can provoke when supplied with articulate, clear technical basic data coupled with the keen interest and participation of the original poster. As was discussed in the original thread, the cause of the hammering was clearly not due to fouling; additionally, the suspicious formation of a condensate liquid level in the channel head (where it definitely should not be) indicated a serious mechanical failure inside the tube bundle. This is a serious process (& design) failure that can yield valuable engineering experience - but the involved engineer must be determined and absolute in his/her attack of the problem and not give up or walk away from it. The success of the exercise is due to Ahmad's initiative and bulldog-like attitude in attacking his problem - but it started with his initially going for help and experience where he could find it and not being ashamed to ask for assistance in finding an answer. Congratulations to all - especially RMW, 25362, SSHEP, and various others. It feels great to see a difficult challenge end like this. Good job, guys. You all deserve a key of beer or a case of fine wine.


Art Montemayor
Spring, TX

 

[rmw]

Gotta admit, my thought process never took me to a blown partition plate, althought it is not the first I have encountered. Usually they are not completely blown away, they are just damaged and leaking by to some degree.

I like a happy ending, and enjoyed the discussion. While it was going on, it was thought provoking. It brought out the best in a lot of participants.

Ghamsa, (Ahmad) you showed some real tenacity in staying with this thing, and some real technical savvy when posting the symptoms for us to ponder. Thanks for letting us know the outcome. It gives value to our (my) participation.

And, Art, it is good to see you post again after a noticable absence. Your participation is appreciated.

rmw

 

[unclesyd]

Please take care in the design and installation of the impingement plate as I've seen tremendous damage caused by such a plate coming loose and rattling around.

I personally wouldn't install it before I get the steam flow under control.