Material for Calcium bromide and Hydrogen bromide

[kissjxp]

I am selecting pipe materials for 50% Calcium Bromide and hydrogen bromide. Can any one with experience recommend the materials suitable for these service?

Thanks.

 

[moltenmetal]

Dry or wet?

Hydrogen bromide as a liquid or vapour?

 

[kissjxp]

moltenmetal:

wet hydrogen bromide (vapor).

One more questions is the material for hydrobromic acid.

Thank you so much!

 

[EdStainless]

Ti
About your only option for bromides above room temp.

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Plymouth Tube

 

[moltenmetal]

From what I've read, Ti will be risky. Though Ti is good with wet chlorine and HCl, the bromides are more aggressive still. Tantalum and non-metallics are your only long-term durability options for wet HBr/conc HBr acid.

The trouble will be if you're neutralizing HBr or HBr acid with calcium hydroxide- Ta doesn't like strong bases, or rather likes them a little too much. Ta has corrosion resistance similar to glass- the same weak points from a corrosion perspective that glass has, Ta tends to share.

 

[kissjxp]

moltenmetal, EdStainless

Thanks for comments. So how about 50% Calcium Bromide?

 

[moltenmetal]

50% calcium bromide in water? Does it even dissolve to that extent? Guess most of the mass is Br- and HBr dissolves to ~50%, so perhaps it's possible. Neutral or acidic? If acidic, you really have HBr with a bunch of calcium ions rattling around, and the previous concerns remain.

If it's neutral (pure water to which pure CaBr2 is added will be neutral), then this is basically a solution very high in bromide ion. Austenitic stainless steels are probably out even at room temperature. Titanium would probably be OK even at elevated temperatures. You'd need to do more research before considering superaustenitics or duplexes.

At room temperature, nonmetallics would still be your best bet with any of these materials. They'd be corrosion immune rather than merely resistant.

 

[blacksmith37]

I know HBr and Br2 are not the same, however; having seen Ti spontaneously burst into flame in liquid bromine at room temp, I would recommend a careful review of literature and maybe perform some testing. (The heat melted the Hast C coupon test rack).

 

[EdStainless]

NO, I wouldn't use Ti in Br, but in aqueous solutions of Br it does very well.
At moderate temps some high alloy SS will work, but the limits are hit quickly.
An alloyed Ti grade is probably called for.
Look at the Timet corrosion guide.

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Plymouth Tube

 

[TVP]

Here is the specific reference to Br, I, and F from the Timet Corrosion Resistance online technical manual:

http://www.timet.com/view.asp?cnct=63&tab=#BROMIDEIODINEANDFLUORINE