Pressure Vessel Erection

http://www.maximumreach.com/Introduction%20To%20Rigging%20Engineering.pdf

Before doing any analysis on it, my guess would be between 2/3 and 3/4 of the vessel height.

Yes. The individual from the organisation supplying the equipment needed to erect the vessel is in a good position to explain, because the location of the <...lifting trun[n]ion...>, the weight and dimensions of the <...pressure vessel...>, the site conditions and the dimensions of the erecting equipment are interdependent.

The ability of the <...pressure vessel...> to withstand the lifting stresses is also a factor to consider, being largely a function of the vessel dimensions, materials of construction, and the ability of the internals to withstand those stresses. This needs to be considered carefully as part of the design. It's no good trying to pick it up if it collapses under its own weight during the process.

More and more the condition of the equipment at the end of its service life is also a factor, as it needs to be able to withstand the stresses of controlled disassembly prior to disposal in whatever condition it might be in at that juncture.

Wow

It's interesting to note that, in the illustration, the top-end <...trun[n]ion...> is actually cylindrical, so that the lifting tackle and its method of attachment might allow the unit to rotate to the vertical.

This video is instructive and informative... Note how that the vessel is lifted by a top mounted central manway, not by a pair of trunions.

This rigging method was probably preferred because of the robust, high pressure nature of the Reactor and the chemical process need for a central manway atop the vessel. (my guess)

Also note the detailed engineering rigging studies made BEFORE the lift

Importantly, also note that, because of geometry and site limitations, how the tailing crane had to reposition itself in the middle of the heavy lift

https://www.youtube.com/watch?v=zFB1-84Olfw