Drying an Internal Floating Roof Tank 2

[sshep]

My Friends,

We are commissioning internal pontoon type floating roof tanks for new products. The moisture specification is crucial, typically we shoot for -50F dewpoint in railcars and vessels for these products (1-octene, 1-hexene, etc). We are trying to keep from generating alot of off-spec material.

After hydrotesting (including floating the roof), all the water will be drained. The floors will be squeegeed and the walls hand dried. At this point there is the concern of small amounts of water remaining around the roof seal.

I will gladly take suggestions for the next step. It has variously been suggested to use some heaters and air movers, or N2 to dry further before boxing up and purging with N2.

Any suggestions are appreciated.

best wishes always,
sshep

 

[IFRs]

You may need to block the seal off the shell to get the moisture there, depending on the seal(s) type.

 

[rmw]

I'm leaning towards the heaters but I don't know how large this tank it or what type of ambient it is in. It is a little of a heat transfer problem if you go the heat route. Will the tank and pontoon roof lose heat faster than you can heat the internal air?

rmw

 

[786392]

Just a wild thought

some desiccant material under the roof with dry Nitrogen blanket might be an answer but may prove very expensive!

Best Regards
Qalander(Chem)

 

[sshep]

Thank you all for making some comments. I think we will put some electric heaters in this tank and put an air mover on top to get some circulation of (hopefully) warm and reasonably dry air through the tank. The idea to wedge the seal off the sides of the tank sounds pretty good, as it will get some air flow where we need it most. Even the desicant is a reasonable idea but I think we will try air circulation first to get as dry as we can before boxing up and inerting.

Anyway, we have a plan using solid first principles aimed at addressing the problem. I really appreciate the advice.

best wishes always,
sshep