plating, anodizing, & finishing Q&As since 1989
Suitability of poly for tank fab
I would to ask you if polypropylene is a suitable tank material for pH=3 AND T=80 C. Please let me know also if itis not used alone is there a special lining to make it suitable.
The temperature you mentioned is at the very upper limit of suitability, and if the temperature ever exceeds this (for example, during startup) it would not be satisfactory. But it is very commonly used for various tanks in a plating shop. Considering the high temperature, you might used a rigid PP tank inside a fiberglass supporting shell.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
What Ted says is essentially l00% correct.
But you didn't say if your pH was due to using an oxidizer like nitric ... and if so, then PP, due to weld failure, would not be suitable. (see # 8169 in the archives).
You could use PP ... duly frp (fibreglass) reinforced but NOT in a FRP shell but BONDED to the FRP. Why? Because there's a helluva difference in thermal expansion but when bonded, the expansion stresses are taken care of IF these two dissimilar plastics are properly bonded together.
A competent dual laminate fabricator can obtain PP sheet with a glass fibre fused to it.
At 80 °C, this is also the max. operating temperature for the PVC:FRP dual laminate. Food for thought, especially if you are using nitric.... but again it's the bond which is extremely important.
Over 80 °C, ah, then you've got to go to PVDF, CPVC or exotic fluorocarbons.... all to be of dual laminate construction.
I hope this helps you a little.
Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
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