What's the effect of SO3 (sulfur trioxide) on Sulfuric acid corrosion?

[Dawoon]

I'm looking for the data of the effect of SO3 (sulfur trioxide) on Sulfuric acdid corrosion.

I found a graph (from NACE Corrosion Engineer's Reference Book) about calculated sulfuric acid dew point in flue gas vs. sulfur trioxide corrosion in 10% water.

And this graph showed that dewpoint was going up while sulfur trioxide concentration went up.

But I don't know what sulfur trioxide concentration means in this graph.

Maybe sulfuric acid corrosion needs water to affect to the metal? So dewpoint is a important criterion for corrosion happens?

If that's right, it's difficult to corrode while sulfur trioxide concentration goes up?

 

[Dawoon]

One thing is incorrect.

It's the graph about calculated sulfuric acid dew point vs. sulfur trioxide concentration in 10% water.

Not sulfur trioxide corrosion.

 

[EdStainless]

There are entire books published on sulfuric acid. The best is the MS series book by MTI (out of St. Louis).

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Plymouth Tube

 

[unclesyd]

What you need to do is look up corrosion data on Oleum.
You will find in various percentages.

From what I remember when we used 125 Oleum was the corrosion rate and mechanics on CS was the same as for the 96% acid.