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Help for corrosion in sulfuric acid condensing system

2005

Hi
We are students of one of the Iran university (www.iut.ac.ir).
One of our chemical industries needs to condense sulfuric acid (H2SO4) by heat. So we need a big pot for this work, and our pot should have two qualities:
1.high temperature resistance
2.corrosion resistance
In our experience , we use alloy cast iron (c =3.19% Si=.3% Ni=3% cu=2%). but we haven't got good result of our specimen. and also the ratio of corrosion increases.
is there anyone who can help us how we should cast our specimen, and what we did wrong.
because we think, that we are wrong by casting the yblock, and unsolution of cu or Ni.
thanks
bye

Amir Masoud Dayaghy
iut - Esfahan, Iran

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2005

Hi Amir,

I can't quite fathom what you are getting at.

You say you are 'condensing' sulfuric acid but didn't say what the initial concentration was nor the temperature.

Going by my (faulty) memory, ordinary mild steel or cast iron is OK for l00% concentration BUT if the concentration drops, OW ! But that was at room temperature. And as the acid concentration DROPS, so will the corrosion increase !

There are some plastics to consider. PVDF, for instance. OK to l40 degr. C ... superb acid resistance ... also available (Fischer, Germany?) as cooling coils.

The next problem, which you didn't mention, is how to perfectly 'condense' those acid condensates .... in a r.t. airstream of 90% sulfuric, an ordinary PVC sine curved
eliminator is pretty successful.

I hope this helps a bit ... if it doesn't, come back !

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

About acid+air corrosion resistant for tanker.

Fariba Jaberi
zanjan - Iran
2006