B-Man wrote:why do you think it benefits a 6" still but not below?
Big rig pretty much nailed it, a 6" has a bit more area to play with, but at yhe end of the day, you don't need that much downcommer.
The design itself is not as efficient as regular alternating downcommers where the refluxed liquid has to go past more steam jets to drop down to the next plate, better efficiency.