Conc H2SO4 and pe100 Plastic pipes

[corrosionman]

My Client plans to store 96% H2SO4 in a 2000 ltre polyethylene tank and the several stub branches are from 32 mm pipes, of pe100 material.
However, I have seen a corrosion chart from a supplier which says Polyethylene is Unsuitable for this concentrated acid, However I've also seen other data which says it is suitable. We hope to get a good life from the vessel and do not want to risk things goig wrong, even in 10 years.
Please has anyone any comments or experience of Conc Sulphuris and polyethylene.

Thanks in expectancy
Corrosionman

 

[rconner]

I would be curious to look at the data that you say supports this use (is the reference e.g. available online?)

 

[moltenmetal]

Commercial concentrated sulphuric acid (93%) is shipped in polyethylene drums and tote tanks.

96% with a 10+ year storage lifetime is another matter. I wouldn't rely on mere compatibility charts for such a selection- I'd want to know the failure modes etc. If the PE is at risk of embrittlement, you're risking a catastrophic crack developing at some point. That would not be good, considering the hazard of the material.

I suggest you go to some major polyethylene tank and pipe manufacturers directly for their advice.

We've had success using polypropylene tanks as basically a liner and forming mold for an FRP tank. This is much cheaper than a proper FRP tank, while also eliminating some of the risks associated with improper FRP construction. I don't know if this is possible with polyethylene, but you could find out easily enough. The FRP provides protection against UV and mechanical damage, greatly reducing the risk of a crack.

 

[moltenmetal]

Just to clarify: polypropylene is NOT suitable for 96% sulphuric acid. I brought up PP just to mention the use of a homopolymer tank as a liner and form for an FRP construction.