HIC corrosion at piping from Amine gas feed to Claus Plant. Material Selection suggestion 1

[Reformator]

Hi,
I need your professional point of view at choosing correct material in my situation. A problem is that piping( elbow of piping) that transfer all H2S from Amine gas feed to Claus Plant have hole due to corrosion. Piping have been installed at 2013 by NACE 0103.
Composition of flux:
H2S – 91%
H2 – 0.02%
CO2 – 0.74%
H20 – 6.9%
CH4 – 0.5%
C2H6 – 0.05%
C3H8 – 0.01%
Operational Temperature: 50 C. Material: Carbon Steel. Pressure:1.81 bar Volume flow:4125 m3/h
Please help me to choose correct Carbon Steel fitting at my condition:
1. WPB
2. WPC
3. WP11 CL 1
4. WP 11 CL 2
5. WP 11 CL 3
6. WP 22 CL 1
7. WP 22 CL3
8. WP5 CL 1
9. WP 5 CL3

 

[Chumpes]

hello
It is not so clear without picture but I could understand from provided information that the detected damage (a hole) was corrosion (more or less generalized ?), not SSC or HIC cracking ? can you confirm this hypothesis or confirm the damage is actually cracking ?
thanks
regards

 

[cap1a79]

Note that HIC is a crack, not a type of corrosion which can induce holes.

Check whether there was temperature increase so that there would be severe localized corrosion due to acid gas (H2S & CO2), HSAS with a function of velocity based on the below reference.

- API 581 Table 2.B.8.2, 2.B.8.3, 2.B.8.4, 2.B.8.5

- API RP 571 clause 5.1.1 Amine corrosion

If you are looking for CS of ASTM, the below would be helpful.

A234 WPB, WPC - This is CS fitting!.
WP11 CL 1,WP 11 CL 2 - 1.25 Cr
WP 11 CL 3 - 1.25 Cr
WP 22 CL 1 - 2.25 Cr
WP 22 CL3 - 2.25 Cr
WP5 CL 1 - 5 Cr
WP 5 CL3 - 5 Cr

Lee SiHyoung,

 

[Reformator]

Thanks for everybody!