Tank height increase

[piiengineers]

We have a crude storaget tank with 1 million barrel capacity. The tank dia is 100 mtr & height is 23.9mtr.The following are the plate thickness adopted originally for constructing the tank.
Plate thickness :11.0 mm top shell, 42.0 mm bottom shell
6.35 mm bottom, 21.5 mm annular
Roof plates – Top & bottom: 5mm – outer rim: 6.4mm

Is there any possibility to increase the tank height by adding addtional shell course in order to store more crude? What is the tank height limit with respect to API 650 for the 100 mtr dia storage tank?

regards,

[arcpro]

Have you gone through API-653?

[piiengineers]

Nothing is specific about maximum height increase and only general statment is available.

[ashfaqanwer]

You would not be finding any limitations in said API standards regarding height of a storage tank. You can increase the tank height after carefully performing the following calculations:
1. Wind forces and moments
2. Foundation evaluation due to additional laoding
3. New stresses along the boundary of tank courses (Finite Element Analysis)
Above three evaluations would provide you with the allowable height which you can increase with everything else fixed.

[mechcolor]

To the best of my knowledge, there is no limitation implied specifically by API design codes for storage tanks.
Increasing height is possible after roof lifting and adding one more shell course. I would agree with ashfaq that you must undergo necessary calculations as recommended by API codes.
I think that the limitation in your case would be the foundation loading and at the maximum you would be able to add two shell courses of 5 / 6 ft (2 m) width. Lets see what your calculations say.

[ben]

No limitations imposed by API 650.
First thing to do: Perform some very simple mechanical calculations like weight added due to additional shell course/s and crude. Just share it with your civil engineer and get his opinion on foundation loadings.
See if he gives a positive sign to your wish.

[ashfaqanwer]

You may like to see a spreadsheet on Tank Design as per API 650 at the following link.
http://www.thepetrostreet.com/forums/vi ... f=11&t=387