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1190 views
04:50 Feb-10-2008

Collin Maloney

NDT Inspector, - Plant Inspector
Applus RTD,
Australia,
Joined Nov 2000
147
Fireside Tubesheet Inspection

We have waste heat boilers with 12m long horizontal tubes 78mm dia x 6mm wt expanded and seal welded between tube sheets - hot side / cold side. The hot side tube sheet is refractory clad with a ceramic insert in the tubes.
Our RBI requires that we conduct inspection.
What would be the best NDT method to locate cracking at tube to tubesheet junction, and corrosion / erosion of the tubes.
There is access only from the tube I.D. and tubesheet face on the cold side.


 
04:57 Feb-12-2008

ranjeet singh

Engineering, Asst.Manager-Condition Monitoring
TATA chemicals ltd.(fertilizer div.),
India,
Joined May 2006
6
Re: Fireside Tubesheet Inspection Mr.Collin Maloney ,
for tube corossion and erosion ,you may select tube inspection technique like RFET or IRIS
For knowing health of ferrule or tube ID surface you may go for Fiberscopy/boroscope
for ascertaining health of TTS joint ,go for Helium leak testing if possible else do DPT or visual inspection.

Regards

----------- Start Original Message -----------
: We have waste heat boilers with 12m long horizontal tubes 78mm dia x 6mm wt expanded and seal welded between tube sheets - hot side / cold side. The hot side tube sheet is refractory clad with a ceramic insert in the tubes.
: Our RBI requires that we conduct inspection.
: What would be the best NDT method to locate cracking at tube to tubesheet junction, and corrosion / erosion of the tubes.
: There is access only from the tube I.D. and tubesheet face on the cold side.
------------ End Original Message ------------




 
09:49 Feb-12-2008
Kåre Johansson
Re: Fireside Tubesheet Inspection ----------- Start Original Message -----------
We have a simillar challenge on our plant and have found a cobination of methodes to be the most effective.

As mentioned by the previous reply some ET techniques will work well, discuss the details with a good inspection company and provide as many details as possible. IRIS will work, but I am sceptical unless you can guarantee against damage to the refractory and ferrules.

We have good experience using video techniques, including laser meassurements of roundness/deformation of the tubes.

Leak testing of the seal welds is a good idea, but then you must have some access to the shell side of the bundle and this wil probably not tell you much about the welds on the hot face. If you have access on the shell side og the tubes I would reccommend you try to do a video inspection on the tubes as close to the hot face as possible. There must be some drain in the shell?

PT/MT and visual inspection of accessible welds is natural if you have seal weld. As you are inside a vesel I would prefere flurorecent techniques. Again you have the problem of lack of access to the hot face.

In my experience all troubles with this type of boilers originate on the waterside. Your best bet is to enforce a VERY STRICT water chemistry.
regards
Kåre Johansson

: Mr.Collin Maloney ,
: for tube corossion and erosion ,you may select tube inspection technique like RFET or IRIS
: For knowing health of ferrule or tube ID surface you may go for Fiberscopy/boroscope
: for ascertaining health of TTS joint ,go for Helium leak testing if possible else do DPT or visual inspection.
: Regards
: : We have waste heat boilers with 12m long horizontal tubes 78mm dia x 6mm wt expanded and seal welded between tube sheets - hot side / cold side. The hot side tube sheet is refractory clad with a ceramic insert in the tubes.
: : Our RBI requires that we conduct inspection.
: : What would be the best NDT method to locate cracking at tube to tubesheet junction, and corrosion / erosion of the tubes.
: : There is access only from the tube I.D. and tubesheet face on the cold side.
------------ End Original Message ------------




 
20:10 Mar-01-2009
Tony McMurtry
Re: Fireside Tubesheet Inspection In Reply to Kåre Johansson at 09:49 Feb-12-2008 .

While water management can be a problem using IRIS around refactory, a little prior planning can keep the problem under control. Internal/external erosion/corrosion can best be identified and quantified with the IRIS unit. IRIS cannot determine if cracking is
present. The inserts would prevent the tube areas beneath from being properly inspected.

 


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