Demolishing of exiting column

[Chris0164]

Hi All,


I am working for a plant in belgium and we have to remove an existing 40 mtr column out of the plant in the shut down. Column is weighing bare 36850 kg and fully dressed (insulation, ladders , platforms and trays) 71350 kg. To be quick we want to lift the column out without removing the internals (bubbler cap type). Has anyone experience with lifting a column withour removing the trays.

I much appreciate your answers.

Kind regards

Chris

Kind Regard,

Chris

 

[swearingen]

It's not uncommon for columns to be removed and then stripped later. Usually time constraints during shutdowns are the issue.

As a design problem, you must chase the forces down. Each tray and appurtenance must be able to hold itself to the shell under shock loading during lift and transport. The shell must be able to transfer these loads to the lift points, and the lift points must be able to handle the extra. The calcs must be performed because you probably don't know if the column was installed with any or all of those items attached. Don't forget to analyze what happens as you lay it down and while it's horizontal.

 

[Cheddarcaveman]

As swearingen says, make absolutely sure of your weight at lift points vs their design lift weight. It is, I believe, highly unlikely that the column was installed/lifted to position with all internals in place, simply because of the risk to the internals during transport/lifting.

It is therefore probable that the lift points are not designed for the full weight you are contemplating lifting!

 

[dtn6770]

With all the engineering issues considered, don't forget appropriate precationary planning.

Have a fully developed lift plan that covers everything from the crane's capacity charts to evacuation procedures. I assume you have the potential to lift over operating equipment. Identify the lines and equipment that could be damaged if something were to go wrong. Identify isolation valves and emergency procedures to cover each scenario. It goes withoug saying to signal the beginning of each lift and to clear the area of non-essential personnel. Consider stopping or limiting your facility traffic during the lift so that emergency vehicles are unabated, if needed.

Yeah I know, it sound very over-kill but there's a time a time and place for everything. If your situation justifies these measures, get all parties on board early on.

Back on the engineering side, if you can't snatch it all in one shot, chop 'er up into smaller bites.