Corrosion Allowance for Jacketed Line

[nitinmech22]

Dear All,

We are currently working on a Sulphur Plant . We are having steam jacketed Sulphur lines.
We have designed the core pipe for 150# class condition and 3 mm corrosion allowance . The jacketed pipe is also designed for 150# class rating and 1.5 mm corrosion allowance. We have designed the core pipe for external pressure as well at 1.01 bar at 150 deg c.

We confirmed from our process regarding the Corrosion allowance for core pipe and they said to keep the same to be 3 mm.

I am in a bit of dilemma that, the corrosion allowance for core pipe shall be 3 mm + 1.5 mm = 4.5 since there will be corrosion on core pipe from both the sides.

Would like to have expert opinions on the same.

Regards
Nitin

 

[SNORGY]

I wonder if they meant that the core pipe should have a TOTAL of 3.0 mm corrosion allowance consisting of 1.5 mm on its inner surface plus 1.5 mm on its outer surface. That would be consistent with keeping a corrosion allowance of 1.5 mm for the inner surface of the jacket pipe.

I have done some sulphur piping for things like pouring blocks; and that is what I have seen in that experience.

Might be worth double-checking if that's what they meant.

 

[Duwe6]

And a 4.5mm total C.A. is not unreasonable if the steam quality is poor. But it is probably 1.5 per side, as SNORGY wrote. RFI - Request for Further Information - time.