Seeking help regarding pitting corrosion of stainless steel vacuum tubes
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Recently, the reaction vessels in the workshop require hydrochloric acid and acetic acid. Since vacuum extraction is needed to draw out these acids, acid mist gets into the vacuum tubes, resulting in pitting corrosion in multiple areas. We plan to address this issue after the projects are completed at the end of the year. Regarding this problem, do any of the senior colleagues have effective solutions that we could use as a reference? Thank you. The image below shows the areas affected by pitting corrosion as well as the temporary measures taken to seal the leaks; some glass sealant was used to fill those gaps
Judging from the picture, it seems to have been contaminated during construction. For example, this phenomenon occurs when a grinding wheel has been used to grind carbon steel pipes and is not replaced before being used to grind stainless steel pipes. At the same time, the welds and heat-affected zones have not been subjected to pickling or passivation!
Did you purchase the stainless steel pipe in accordance with the design standards? In fact, stainless steel pipes are also divided into national standards and American standards. There are also many implementation standards
It was 304 stainless steel that was chosen after various considerations back then; it turns out to have been a mistake
With hydrochloric acid, why use 304? What’s your thinking? Change the material of the pipes; otherwise, corrosion will be more severe during normal operation. PPR or fiberglass-reinforced plastic could also be used
Well, thank you. This is a solution; thanks. Proper consideration wasn’t given during previous production, which is why testing has continued to this day
The true solution is to prevent acid from entering that section of the pipeline~~~~ As a hint, there is a device that works well in such conditions: it’s called a “wire mesh demister”...............
Brother, thanks. I’ll look into it later to see if it works for acid mist
It seems someone is taking bribes. There’s nothing that can be done about it; this phenomenon is just the beginning, and it will get worse in the future, even more so…
It’s hard to put into words; leaks and problems have their reasons, and perhaps a lack of professionalism is part of it