Tank Buckling, Vertical Storage tank buckling,

Is to discharge or intake? How far does pipe extent inside tank?

It is steam inlet to the tank at 8 M high. 24" pipe is perforated and open at the end, allowing steam to get condensed in the tank and runs all along through almost the centre of the tank, but not exactly through the diameter

Thanks

Srijit

With as little info is akin to shooting in the dark but could the buckling be caused by a by-product of the condensation process; in effect an immediate reduction of pressure at the plate surface? or a vacuum if you will?

Srijit,

My guess, and it is only a guess on the given information, it that the buckling is caused by thermal expansion of the 24" nozzle. You say this nozzle is almost the length of the diameter of the tank - 45". Due to thermal expansion a stainless steel pipe will lengthen by approx 1.2" given the temp. of the steam is 100% (if the steam super heated it could be a lot more). If the pipe is welded to the tank at both side (structural angles) this may cause the buckling of the shell plates.

The reason it did not affect the 16" pipe could be that the smaller section allow the pipe to deflect (bend) in the middle to allow for the elongation. The larger section pipe will make the whole system more rigid.

Your initial question was if there was something to Analise the system. The easiest way would be to find someone with a Finite Element Analysis package (such as the add-on to Pro-Engineer) - Draw a solid model of the basic system (include all support brackets and material types of tank, brackets and nozzle). Test the model using operating temperatures. Even running the basic simulation will identify the problem.

However, if this sounds like the answer, don't bother with FEA. I would just modify the brackets to allow for the expansion.

Regards

J.

My earlier reply was just to describe the system, the buckling has nothing to do with the process or steam condensation as the tank was on shut down for the last one year.

Initial buckling was said to be during hydrotesting of the pipeline connecting the nozzle.

I took initative to repair this buckling 6 months before

Replaced shell section at nozzle area

No signs even 3-4 days after welding of horizontal / vertical shell weld joints, but 1-2 days after welding of pipe to shell.

Buckling increased to beyond limits in 6-7 days after removal of temporary stiffeners from inside

Srijit,

Excuse my ignorance - This system is used for condensing water- correct. Can you explain the system.

Could you attach a freehand sketch of the system so the forum could get a better idea of the problem. You did not mention:

material type(s)

pressure/temperature differential - tank/pipe

Direction of the deformation of the tank.

Loading on pipe due to fluid movement inside the tank

Is the pipe submerged in water. Is it displacing water and therefore placing extra loading on the pipe. i.e. floating.

Regards

J.

Maybe the buckling is the result of the additional load of the larger diameter pipe that is to be supported by the wall section.

If the pipe is the same wall section, then it would wiegh nearly double the previous pipe and acting as a cantilever through the wall would have significant leverage on the wall. If the buckling is "out" below the pipe and "in" above the pipe, then that is a possible explanation.

The support brackets will stop it "shearing" down the tank wall, but the moment created by the weight and length will be significant.

Dear Sir

we are dealing with adding new ambrela type roof (fixed one). we would like to receive relevant code that guides minimal thickness required and buckling problems.

Many thanks