Pressure vessel internal coating damage

[kennym]

Dear All,
I have very limited knowledge of Thermography and I am seeking guidance on feasability of a possible application.
Wondering if Thermography has been or could be used to reliably detect presence of localised internal coating breakdown on a lined (similar to glass flake application, around 600 microns thick) pressure vessel or tank.
Inspection would be performed whilst onstream, with the vessels/tanks containing hydrocarbon product at typically 50-100 degC.
Vessel/Tank wall thicknesses will range from around 10-30mm nominal.
External coating is a grey, gloss-type finish.
I would obviously follow-up any indicated internal coating loss with conventional NDE techniques to check for any metal loss.
Any relevant experiences?

 

[gsfitzsr]

kennym,

You can probably do what you want, but it might take some creativity on your part.

The internal glass lining will act as an insulator somewhat, so you might be able to see the cooler areas where the lining is good.

Try to get data during a windy or cool day and see if convection cooling is helping to reveal the areas where the lining might be missing.

If there are large swings in your product temperature you might be able to see the areas during those transients.

Greg F

 

[gsimson]

Thermography can be used as an improvised tool in any application where the source of heat is directly visible comparision with adjuscent point should be possible. The source of heat can be - Loose Electrical contact, end cover of a defective bearing, defective pipe lines carrying Hot/cold liquid,etc.,
The method is very simple and direct without any FFT or Spectrum. With a bit of skill to capture the temperature difference Thermography can be improvised in any application.

 

[NOx]

Not too sure of the process, but the following can be utilised to monitor hot spot detection through permanent deployment of fibre optic cabel deployed around the vessel and monitored via DTS. By utilising DTS the system provides an early warning system of failure and helps monitor for lining wear and may also provide benefits with respect to process monitoring. The alarm zones can be as many as 500 and set to minimum / maximum / average as well as rate of rise and fall.
This technology is available on a retrofit as well as new build basis.
Complete temperature profiles can be displayed on a PC or alternativly a graphical user interface can be provided that mimics the vessel with different temperatures represented by different colours.