Welding carbon steel at high temps??? 1

[MadDog88]

We have a refractory lined, carbon steel collection header which has sustained localised refractory damage and subsequent hot spots. We are unable to shut the process down to repair the refractory so I want to investigate an on-line “temporary” repair.

I am proposing to weld nozzles onto the vessel on-line in the areas of localised refractory damage (temps up to 930 OF when steam cooling is removed), hot tap into the vessel and inject liquid refractory into the void areas. To make it more interesting, the vessel contains hydrogen gas at approx 2000 kPa (290 psi).

Things I am wondering are;

· Will welding at these high temperatures cause excessive stresses in the joint when the system is eventually cooled down (hopefully in a year or so).
· Can welding be successfully carried out at these shell temperatures?
· Will the existing refractory be damaged by welding (shell is 16mm thick).

Any help on this subject will be appreciated.

Thanks

 

[unclesyd]

You had better shut the line down and repair the refractory as soon as possible.

If you get a H2 leak and the resultant fire you will have a melt down of anything close.

H2 isn't interesting it is very dangerous.

 

[Istre]

Wow. Take a look at the Hindenburg footage, and then realize that your pressures are WAY higher than that, so not only is there possibility for fire, but you could possibly set up a pressure vessel explosion. Welding on a vessel full of hydrogen is extrememly ill-advised. There's a high possibility of Darwining someone on this one.