Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
(OP)
Hi we have been using a dry break coupling on a tanker offload facility where we offload 36% HCL at ambient temperatures.
The dry break coupling has been in service for approximately 1 year and the material of construction is hastelloy C22. We had a PMI test carried out to confirm this. The coupling recently started leaking and we disconnected it and found that it was corroded inside, see attached images.
When we specified this we did not see any issues with using C22 on HCL duty at these conditions and did not expect it to fail after 1 year in operation.
Has anyone had any experience with corrosion of hastelloy C22 at ambient temperatures? We will be sending this to a metallurgist to further investigate but was looking for other opinions as to the cause.
Thanks

https://res.cloudinary.com/engineering-com/image/upload/v1478260515/tips/N257D4401-1_feqp3q.pdf
The dry break coupling has been in service for approximately 1 year and the material of construction is hastelloy C22. We had a PMI test carried out to confirm this. The coupling recently started leaking and we disconnected it and found that it was corroded inside, see attached images.
When we specified this we did not see any issues with using C22 on HCL duty at these conditions and did not expect it to fail after 1 year in operation.
Has anyone had any experience with corrosion of hastelloy C22 at ambient temperatures? We will be sending this to a metallurgist to further investigate but was looking for other opinions as to the cause.
Thanks

https://res.cloudinary.com/engineering-com/image/upload/v1478260515/tips/N257D4401-1_feqp3q.pdf




RE: Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
book: Materials Selector for Hazardous Chemicals (MTI Publication MS-3)
anecdotally, we use fluoropolymer lined equipment for all HCl offloading.
RE: Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
Same here- I wouldn't mess with alloy components in a concentrated acid environment at room temperature. Polymeric materials and linings are just far more likely to last long term.
RE: Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
I'm not sure why Hastelloy was specified as all other equipment we have on HCL duty is lined but I wouldn't have expected them to fail after only 1 year in service.
RE: Hastelloy C22 corrosion on ambient temperature HCL duty (36%)
I would not use metal in HCl service where there is any option.
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P.E. Metallurgy, Plymouth Tube