Has anyone had experience in Polyph 2

[david339933]

Has anyone had experience in Polyphosphoric acid vessels? Curious as to an acceptable material....316L?

 

[MJCronin]

These might help, .... Consider posting in either the "Chemical Plant design" ... or "Boiler and Pressure Vessel" forums

What is the volume you wish to store ?... and at what temperature ?... Storage inside or outside ?

https://smc-global.com/wp-content/u...HORIC_ACID-All-Grades8017-16-1_GHS_031315.pdf

https://nj.gov/health/eoh/rtkweb/documents/fs/1516.pdf

My experience is that it usually best to contact the bulk seller of the acid and ask him about his methodologies and material selections ...

More information, please ... what about piping, pumps, valves and gaskets ???

MJCronin
Sr. Process Engineer

 

[btrueblood]

Keep fighting the good fight, MJ.

 

[david339933]

Thanks MJ, I know it must have been hard to bite your tongue, with the limited info given.
Volume is only 50L - 75 psi @ 300F.
I have been given specs by the customer for a vessel, but was curious as to materials normally used, as I have never come across this acid.

 

[EdStainless]

So this just refers to acid over 68% P2O5.
Do you have an actual concentration?
It can run clear to 105%.
Once you are over 85% the freezing point is room temp or higher.
The 100% acid is 42C for freezing point.
And it is a bit like syrup for consistency.

Transportation tanks:
"For superphosphoric acid,type 317L (S31703) or 317LN is used,as also alloy 2205
(S31803). The duplex alloy 2205 has higher strength than the fully austenitic grades
and has a coefficient of thermal expansion more closely matching that of the steel
vessel."

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P.E. Metallurgy, consulting work welcomed