How to Determine Optimum Vessel Diameter and Length 2

[Yenrich]

I have been assigned a project to design a 50 m3 LPG storage tank to ASME BPVC Section VIII Div 1. I am having a challenge on how to determine the optimum diameter and length for this vessel in metric units. Could anyone please explain to me how I can determine this?

 

[StoneCold]

Yenrich
The science behind the diameter of most tanks is this. How big a diameter can travel over the road with out too much trouble? That is usually the answer to your question, then when you calculate the length you ask the same question. If the numbers are too large you break the tank into two tanks. If you have other options like rail or barge for delivery then you can make different choices for the geometry. If you are building the tank on site (probably not for 50 meter^3 tank) then you have even more lead way with diameter vs length.
In your case the answer is probably 3.5 meters in diameter and 22 meters long.


Regards
Brad Stone

 

[Yenrich]

Great. I get it now. Been grappling with this problem for a while. Thanks So much. Further to that, why 3.5 m?

 

[StoneCold]

Yenrich
I chose 3.5 meters as that is about 12ft which is the maximum you can get away with in the US. Even then, you need special permitting to move the load over the road.
Your number may be slightly less, I don't know where you are.

Regards
StoneCold

 

[JStephen]

If there are no other constraints, just leave it to the fabricator to pick most economical dimensions.
If you are the fabricator, then try it several different ways and see what works out cheapest and you'll know next time.
In some cases, it is advantageous to make the shell length or the circumference match up to plate dimensions that are readily available.
In some cases, you'll want to hold the thickness small enough that it doesn't require stress relief.
Head suppliers may have various limitations as well.
Crane capacity or overhead room or rolling capacity could all enter in, in some cases.

 

[Yenrich]

Thanks gusy. I really appreciate your contributions. I understand this clearly now.

 

[geesamand]

If the tank contents need to be agitated, contact the agitator manufacturer early enough to select tank proportions suitable for the mixing process and to keep the mixer cost down. I have been in enough situations where the tank is several times taller than it is narrow, and the mixer shaft has to be long and the mixer gets quite bulky and expensive to control the critical speed of the agitator.

David