Re: Column Reboiler problem

From: <Rajesh_V_Balapure@ril.com>
Date: Fri Sep 13 2002 - 00:16:00 EDT

HI ,

           Tanmoy ,
                            The problem of mismatch of reboiler requires

more Details like whether each springs are mounted separately below reboiler or the common structure is provided below the reboiler to rest on spring load flange .
In absence of struture each spring may act differently which could cause reboiler lugs to tilt either side spring In this condition also the lugs will touch to load flange of spring but could cause mismatch or increased loads at nozzle.Try analysis with independent springs at lugs & with common structure modelling as rigid element and then spring & find a difference at nozzle point.

Regards,
Rajesh Balapure.

Tanmoy Saha <Tanmoy.Saha@Halliburton.com> on 09/12/2002 05:24:37 PM

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Subject: [PipingDesign] Column Reboiler problem

Hi all

This is a problem observed and raised by one of my friend. My views are as below

Information is not complete. Further information like full detail of the column at least the distances of the nozzles from bottom tangent line of the
column is required.

However it looks like it is not a stress problem as there is mismatch of two
nozzles. If it was a stress problem both the nozzles should have deflected same way and there shouldn't have been any relative displacement. Possible things are

1. the nozzles were offset at the beginning itself and forcefully joined by some tricks. (most likely)
2. the tower and the reboiler were not at the same temperature which is less likely.

Am I correct? What do you think?

Thanks

Tanmoy Saha
Kellog Brown & Root, Singapore.
Ph. 6422 2535
Email. <a href="/group/PipingDesign/post?postID=o5_xdlrnlvKe-yVkAu_TLQZ9B9byytaQKlFqCuK7FwRfIb34DOJ1C25axsGy7379dL1z4ZdiojAroTlTmIBjBVtqVXI">Tanmoy.Saha@Halliburton.com</a>

Problem:

COLUMN

              Reboiler
                                                       80" connection

Reboiler
Flange

4 Lugs
2 Springs

   per lug

There is a column with a reboiler connection of 80" size. The reboiler is supported on 4 lugs and there are 2 F type springs below each lug. Each spring takes a load of about 10 tonnes. The reboiler is very heavy. The reboiler is supported on a separate concrete structure. After about 8 years of operation client found out that the 80" connection nozzle flange and the reboiler body flange were leaking. So to replace the gaskets the reboiler was disconnected at the the 80" nozzle flange and the body flange. When they were refitting the removed part of the reboiler back to the original position, they first connected the 80" nozzle flange. Then they found out that there was 10 mm gap between the two body flanges. Nobody is able to guess what happened. The lugs are still touching the spring load flange. The pointer on the flange is at topmost position and not
at center.
There are 30" piping connections on the downward part of the reboiler.

Can u suggest any reasons what could have gone wrong ??

[Non-text portions of this message have been removed]

Texas Flange - a good source for information on industrial flanges, all they ask is for referrals for designs they help with. 877-610-8924.
www.texasflange.com

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Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Fri Sep 13 00:16:00 2002