4 replies to this topic

[chemsep05]

I believe there is some usefull stuff in Perry's ch13-15

[siretb]

It's simple and useful to use a F factor; the F factor is more or less the square root of a kinetic energy
F = U * sqrt(rhov) where U is the vapor velocity (m/s) and rhov the mass density (kilogram/m3) of the vapor.
The packings, depending on their intrisic capacity have maximum F factors between 1 and 4 m/s sqrt(kg/m3)
Knowing your vapor rate, the shell diameter and the packing type, this will immediatly tell you whether this packing is OK or not.
For tray replacement, a first approach with a structured packing like the 250Y (Sulzer) is not bad. Sulzer has a software, free to download, that calculates the capacity, but it's easily done by pencil & paper. For 250Y maximum F is about 2.5 at atmospheric pressure.

As a second step, then you will take into account the liquid rate, using capacity curves.

You may want to look at the Perry's handbook, or Kister's books (distillation operation or distillation design)