Cl Stress corrosion hydrogen plant

[deklerk]

Does anyone have experiece of Stress corrosion cracking of 304 Stainless steel components in steam reforming plant in low temperature shift converter section ?

Thanking in advance.

DEKLERK

 

[Yordif]

If you have Chlorides in the LTS you have a serious problem. CL is major poison for LTS catalyst. Actually, most LTS catalyst (ZnO / CuO blends) is a pretty good Cl trap but it generally does so at the expense of the LTS catalyst activity. So if you are really experiencing CL induced stress corrosion cracking I would suspect that your catalyst bed is severly underperforming.

If you do have incoming CL's, then some sort of HDS followed by alumina should be in place infront of the SMR to remove the CL's early in the system.

If you suspect a poisoning event, monitoring the % exoterm between the LTS interbed thermocouples can narrow down the timing of the event and help you to predict your current catalyst die off rate. Certainly your catalyst vendor can help with this analysis. Gayesco also has a paper on this which can help if your bed is underinstrumented. A good Syngas Plant reference is "The Catalyst Handbook" by Martin Tygg. It worthwhile to have a copy if you are involved in a hydrogen plant.

 

[EdStainless]

Where in the system? What are the temps?
I have seen thermal fatigue that is almost impossible to seperate for SCC.
3XX stainless has such large thermal expansion that minor temp fluxuations, if they are rapid, can create large strains.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm