When measuring media containing hydrochloric acid, the temperature probe’s sintered PTFE layer cracked
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Help: The medium in our reactor contains 3.7% hydrochloric acid, the temperature is around 100 degrees, and there is no stirring. Temperature measurement is carried out using sintered PTFE sleeve thermometers, which crack after 3 to 6 months of use. Theoretically, PTFE is resistant to heat and acids; so is it the manufacturing quality of the instrument manufacturers that is inadequate, or cannot sintered PTFE be used in such operating conditions? ? There is also a similar help post on Baidu Tieba. I’m not sure how effective Hastelloy C is for measuring the temperature of media containing hydrochloric acid; those in similar working conditions, please offer some guidance. I am extremely grateful. .
I used the exact same image from Baidu Tieba
Tantalum pin temperature measurement is basically a standard feature of reaction vessels.
3.7% hydrochloric acid at 100 degrees Celsius: stainless steel, Hastelloy C, and titanium cannot be used; tantalum can be used, but the effectiveness depends on the specific application. It seems that when the temperature of tantalum exceeds 135 degrees or 185 degrees, corrosion can also occur in this medium environment. Speaking of the process for tetrafluoro linings, the sintered tetrafluoro method should not be used, as it is difficult to achieve a complete and seamless integration of the lining and the head. To address this situation, the extrusion molding process can be employed to ensure the integrity and consistency of the sleeve.
……It seems to be a problem with the PTFE sintering process; using a PTFE-lined version would work for this type of application :)
By using PFA material for spraying, it can withstand temperatures above 200 degrees, and the spraying thickness can also be customized
Using PTFE for this operating condition is no problem
Buy a solid PTFE rod, place it on the lathe, and drill a hole in it; make sure no ventilation holes are created. That’s fine. Why not use glass-lined steel or glass?