Is hydrogen bake-out of small bore piping in wet H2S service necessary
Is hydrogen bake-out of small bore piping in wet H2S service necessary
(OP)
My refinery has always done this in the past but I'm not sure it is necessary (small bore piping <2" and service with H2S >50 ppm in water phase). Would it be sufficient to maintain a preheat of ~200 degF, use E7018 low hydrogen electrodes, and follow up with a PT 48 hours after welding, assuming there was no history of cracking in the service or hydrogen blisters?
Thanks in advance,
- David
Thanks in advance,
- David





RE: Is hydrogen bake-out of small bore piping in wet H2S service necessary
RE: Is hydrogen bake-out of small bore piping in wet H2S service necessary
I guess I should expand the question to include any thin-walled pipe (<= 1/2"). Thin walled piping in wet H2S service is usually relatively low pressure in these cases (< 200 psig) which is why I'm thinking we don't need to do bake-outs as often as we have in the past.
How does everyone else handle new-to-old piping in hydrogen service?
Thanks.