Design of 30 tonne split water tank

[engoz]

Hi there,
I need to design a 3m high 3600mm diameter split water tank with a capacity of up to 30 tonnes of high temp water open to the atmosphere. There is not enough room for two tanks and this tank will be built over the top of the old one.
One side will be full most of the time and the other side will only be used when the water from one side is diverted when found to be contaminated. I am thinking as one side is going to normally be empty that I will have hoop stress problems and the like. I am looking for any information on open atmosphere split circular tanks. Does anyone know where I could find this?

Thanks in advance,

DC

 

[mduplessis]

engoz
I have no experience on such tanks but just a thought; why not use concentric cylinders? I guess you will have less problems with stresses since both tanks will be cylindric. The effect will be the same as simply splitting the tank through the middle.

 

[butelja]

Concentric cylinders are definitely more feasible, because you still have membrane rather than bending stresses. Any flat plate caries a load via bending stresses, which is much less efficient than membrane action. A circular tank with a straight dividing baffle would need VERY thick plate for both the baffle and the shell.

 

[MJCronin]

All excellent advice above......

My experience has been that anytime that you depart from a cylindrical, vertical axis tank, your costs go up quickly.

If it is at all possible, even if you use small diameter, tall tanks, stay with the cylinder design (API-650 etc)

I have found that, the maximum height to diameter ratio for "tall skinny"steel tanks (filled with water) is about 3.1-3.5.

The only time that partitioned cylindrical tanks make sense is when they are on a horizontal axis and have an extra "head" welded internally. (See the Highland Tank website

http://www.highlandtank.com)

Good Luck !!

MJC