LPG sphere thickness 1

[Weldinspect]

Hello friends, I am doing a rougth budget for 6 LPG spheres, does any one have the thikness of a 19.5 meters sphere?
Thank you

 

[JStephen]

I suggest you contact some companies involved in building spheres in your area and get information from them (not the thickness, the budget price).

 

[Weldinspect]

Thanks JS but this is a preliminar calculation for a budget only, asking a company would probably require a payment from them. My calculation right now is of 8.5" and just want to know if there is any experienced collegue who has buitl a similar one...

 

[JStephen]

From a blurb about a recent tank:
"The largest Sphere holds 50,000 BBLS of Propane at 250 psig in an 81'-10 sphere. The Sphere has an unusually high design pressure that requires that all welds be 100% Ultrasonic Tested(UT) for quality. Also due to the high pressure, the plates were designed to be very thick (the thickest plate was 1.918") and required that the Sphere be field Post Weld Heat Treated (PWHT) by holding the entire sphere at 1,195 degrees F for 2 hours. Before being placed into service, the Propane Sphere was then successfully hydro tested under pressure to 358 psig."

IE, that particular tank was 25m diameter with 1.918" plate at 250 psi. This was using higher strength material, so it wouldn't be strictly proportional to pressure or diameter if you scale it up or down. But should give you some idea.

 

[Weldinspect]

Thanks JS, this helps me a lot to have an estimate of the material to be used.

 

[MJCronin]

Please do not neglect the cost of the elaborate foundation for this massive sphere in your evaluation

Most existing spheres load the ground in a circle of pillars, unlike the uniform loading of a flat bottomed tank. I am aware that not all sites can be used for FB tanks, as the developed unit ground force may require an unecononomic foundation design.

I hope that you considered other shapes and multiple tanks in this evaluation.

An interesting discussion of LPG sphere sizing is here:

http://www.cheresources.com/invision/topic/10530-lpg-spherical-tank/

Respect the members of this forum......let us know about your final decision

MJCronin
Sr. Process Engineer

 

[Weldinspect]

Thanks MJ, I apreciate your advise and I will show my client this information that I know will be very usefull.-
If I work at this project I will send pictures...

 

[Duwe6]

40-footer tends to be 1" thick. And that is after 100% volumetric weld testing - RT, UT, PAUT [100% joint efficiency]

Unless you are only calculating shipping weight, your estimation will be too low and WAY off base. Fabricating 1 to 2-inch thick steel into a spherically curved section is not a trivial exercise. Erecting those curved sections, and welding them expeditiously and soundly is not trivial either. Then comes the In-Situ PWHT, with no localized hot or cold spots. Also tough. Call CB&I - Chicago Bridge & Iron and get an 'order of magnitude' estimate. They will want diameter/volume, MAWP & MDMT, and the fluid to be contained. They MIGHT be able to give you an idea about the cost of the piles that the legs will rest on. They will be able to spec the max. allowed settlement per leg, and the design loading.
These are the only folks I would trust to build me a sphere. Currently have two from the 1960's - excellent condition, excellent quality.

 

[MJCronin]

WeldInspect,

Please explain the reason why more expensive spheres are required for this project, rather than the mass-produced and cheaper LPG cylinders.

I certainly hope that your answer is "that's what the client wants"....

Was a cost comparison made ?

So often I have heard "The client wants what the client wants"......... up until the last moment when he gets changes his mind.

MJCronin
Sr. Process Engineer

 

[MJCronin]

http://www.lpgspheres.com/

MJCronin
Sr. Process Engineer

 

[Weldinspect]

I believe in This case the client may not know exactly what he needs and I will study this subject further and explain him. Thanks a lot MJ

 

[Weldinspect]

@Duwe
CBI know a This market they have buit thanks before, and I dont know if my client wants to ask them and yes I will study further The cost comaparisson thanks

 

[Weldinspect]

Writing from my movil doesn´t seem to be correct but anyway CBI is well known here

 

[MJCronin]

Weldinspect,

Please complete this thread and respect us...

Share with us the results of your final tank evaluation and tell us the reason for your choice.

Best Regards

MJCronin
Sr. Process Engineer

 

[Weldinspect]

I will be glad to let you know the final designs and maybe even the advances in future construction sometime next year MJ