Reboiler Supporting

"What factors decide whether the vertical thermosyphon Reboiler should be supported from the Column or on a Independent Structure?"

That is a very good question.
Consider the following:

- Client preference - What does the client want or does not want? What does the Client have in his existing plants? What benefits or problems does the present methods present to Construction, Operations or Maintenance?

- Do the soil conditions at this new site present any potential conditions that suggest one method would prove better than the other method?

- What is the size of the Column? - Is the vessel too small to hold itself up and act as a support for the Reboiler?

- What is the size and weight of the Reboiler? How many Reboilers are there going to be (I have had situations with 1 Reboiler, 2 Reboilers and 3 Reboilers)?

- What is the size of the piping between the Column and the Reboiler? - If the connecting piping is too large then the Reboiler may be "pushed) too far out from the vessel and act as an unbalanced load that is unacceptable to integrity of the vessel and the foundation?

- If an independent structure is used will it be supported on the same "spread footing" as the Column? If not placed on the same (underground) spread footing what provisions need to be made to compensate for uneven settlement?

- What kind of independent structure would be used, Reinforced Concrete or Fireproofed Structural Steel?

- If an independent structure is used what considerations need to be made for maintenance access to remove the a) bottom Reboiler piping, b) the bottom Reboiler Channel Cover of the Reboiler, c) removal of the total Reboiler?

- What effect or impact would an independent structure have on the construction sequence, construction access and construction scheduling

No mater which method you end up using the Reboiler support elevation (attachment to the Column and to the Reboiler) needs to be as close to (even with) the Columns bottom tangent line as possible. That way all growth from the support up will be the same and all growth down will be the same and you will not overstress the nozzles.