Hi!

We have a Nitric Acid storage tank (13 m height x 15 m ID; 5 kPa internal pressure, 80ºC design temperature).

We are in the Feed Stage and the estimated price for a concrete bulkhead in case of leakage is too expensive since we don't have enough area in the surroundings of the tank, so the height of this bulhead will be like 6 m to contain 1.1 x tank volume. It is going to be built on site (Australia) and it seems that the labour price there is too expensive...

Well, the client has suggested that if we make this tank a double walled tank maybe the costs could be reduced, but we are not sure about that.

I will really appreciate if someone can recommend me some paper or based on your experience this is a good idea or it has senselessness. I will be happy to hear any ideas you might have!!

Also, in case of bulding a double wall tank...it would be better a steel-steel or a concrete-steel wall tank? Which are the advantages and disadvantages of each one?

Lots of thanks in advance.

And again, congratulations for this great forum! :)

Steel-Steel double-wall / double-floor would be my choice. The leakoff drains will have to be checked for leakage, and that check put into the Ops Log regularly [weekly?]. Also, you will need some provision to catch overfill spillage.