The problem of acid color change caused by the acetic acid pump
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The company previously used Eweichi magnetic pumps for acetic acid circulation, with a specific gravity of 1.054–1.1 and a temperature of 60 degrees. We are currently carrying out localization upgrades and would like to inquire about domestic pumps made of PTFE material. There is a question: the site manager mentioned that in the past, acetic acid was circulated through pumps and changed color as a result. Dear friends, has this situation occurred where PTFE tetrafluoro material was used to transport acetic acid? Also, most domestically produced fluorine-based material pumps are made of FEP. What is the difference between the two?
It’s probably not a material issue, but rather some other problem with the manufacturing process
We have many cases of using tetrafluoropump systems to transport acetic acid, but we’ve never heard of the fluid changing color after circulation; the exact reason is unknown, though it might be due to the processing factors mentioned earlier. The poster is right; domestic perfluoroelastomer pumps are made of FEP material. Since FEP is easy to shape, can be processed by heat melting, and has good fluidity, their corrosion resistance is actually the same.
It’s not a problem with the material of the pump; it’s probably the discoloration caused by the recycled acid
It is likely corrosion of the metal material in the pipeline
The material should be fine; PTFE has strong resistance to acetic acid corrosion. It’s likely a process-related issue. In our factory, we use 316L stainless steel pumps for acetic acid circulation or transfer, while titanium pumps are used in special operating conditions