Column & Thermosyphon Reboiler: Load Interaction

[ConstantEffort]

Distillation column and an independently-supported, vertical thermosyphon reboiler parallel to the column.

The reboiler is on its own structure to support weight. It is free to slide though to accommodate the thermal expansion between it and the fixed column. This also means that wind and seismic forces from the reboiler will transfer across to the column.

We buy out these vessels from different suppliers. To date, no one has really thought about the interactions between the two. That is to say, the skirt calculations on the columns only consider the overturning moment of the columns themselves.

How do you address this situation?

Am I off base to think that the column should be designed to handle the combined reaction?

Does anyone sub the whole package out a single vessel shop which takes full responsibility for both vessels and the pipe between?

 

[Duwe6]

"This also means that wind and seismic forces from the reboiler will transfer across to the column."

That's your answer; calculate them as a complete assembly.

As for Std. Practice, the Design Team for that assembly was supposed to look at the interactions BEFORE they spec'd out the column and the reboiler. A 'generic' column will probably not have a strong enough skirt to take the combined seismic or wind loads. A 'generic' thermosyphon will probably not have enough nozzle reinforcement to accomodate the wind-loading [swaying] of the column, say nothing of the seismic movements of the column.