Is tantalum resistant to hydrogen chloride corrosion? Is C-276 resistant to hypochlorous acid corrosion?
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Now, let’s take two examples from the factory and ask everyone to pay attention. 1. Tantalum-lined pipeline: Carbon steel pipeline with a loose tantalum lining. During use, after two months, micro-leakage was detected in the tantalum lining. Medium temperature: 200°C, dry hydrogen chloride gas. 2. Blasting discs: Hastelloy blasting discs. In contact with chlorine gas and a small amount of water vapor, a wet chlorine gas environment. After two months of use, the rupture disc corroded and broke. According to the information, neither of the two materials mentioned above should have any problems under the aforementioned operating conditions. Could everyone please help figure out where the problem lies? Thank you!
I have used HC22, with an acidic ethyl acetate (hydrochloric acid) medium, which is corrosion-resistant. Additionally, when it comes to material selection, why not use fluoroplastic-lined pipes for the rupture discs and pipelines? For the rupture discs and clamps, those coated with fluoroplastic can be used.
Additionally, tantalum exhibits good corrosion resistance below 150°C; this is for reference only
Above 150 degrees? We use it on hydrogen chloride dried gas pipelines at 200 degrees.
The pipeline is lined with PTFE, but the burst disc does not have a lining. Initially, 316L with a lining was chosen.
At temperatures below 150°C, tantalum is one of the metals with the most stable chemical properties. Only fluorine, hydrofluoric acid, acidic solutions containing fluoride ions, and sulfur trioxide can react with tantalum
What if it’s above 150°C? How about around 200°C? ?
There could be more than one factor contributing to leaks in the tantalum lining; 200 degrees should be no problem, and some manufacturers use 280 degrees without any issues as well. Is the medium pure HCl gas?
The corrosion of Hastelloy still depends on temperature and concentration; HC22 should be usable up to 95°C, and in some cases titanium and niobium can also be used
It is recommended to use imported HASTELLOY C-22 alloy; please contact me if you need samples for testing