Tie-in H2S and SO2 containing pipework

[pontfoort]

Hello,

I'm currently working on a project where H2S is removed from the proces gas by means of a Claus unit and SCOT unit.

I'm aware of the problems when making a tie-in in existing Liquid Sulfur carrying lines. However, what to do with lines that contain NO elemental Sulfur but only H2S/SO2, etc? Can I make a tie-in by cutting and welding or do I need to replace complete sections from flange to flange?

So far I have not found much literature on this subject.

greetings

S

(The Netherlands)

 

[stanweld]

Your primary problem is dissolved hydrogen. Proper dehydrogenation heat treatment prior to welding and proper preheating during welding must be done. EWI has much info in this regard, especially with regard to hot tapping.

 

[NickelMet]

If you need information on baking out the steel due to hydrogen, see the book "Welding Steels Without Hydrogen Cracking" by Bailey, et.al. (2nd edition). It was published by Abington Publishing and I think I found it in the ASM International catalog. Chapter 5 is the one that might interest you.

~NiM