Which is the best material for built a distillation tower for separate acetic acid, benzene and fenol?

Question

and what is the difference between have rashing rings or bubble "dishes"...

I am sorry I do not know if the terminology is all right, i hope you can understand me.

Answer 1

well, the materials of construction depend on several things, including the kind of tower (temperature and pressure of operation), the concentrations of your materials, and the sensitivity to contamination for your final products

one of the common stainless steels would be recommended depending mostly on the acetic acid content and moisture (water contaminant content)

rashig rings are a type of packing (fill) for a column

packed columns are made by filling an empty column with a big "pile" of packing elements
the packing elements (rashig rings, beryl saddles, and many many other configurations) because of their irregular shape, fill the column but leave it mostly empty

the mass transfer contact comes as the vapors and liquids contact pouring through the network of holes formed by the packing

tray columns are built by installing "trays" in the colunm every few feet (or sometimes much closer) in the tower

these trays have holes in them to let the liquids pour down and the gasses bubble up

"sieve" trays are more or less just flat sheets with holes in them

"bubble cap" trays have the holes covered by a special cap that doesn't let much liquid down, only gas up, and the liquid overlflows the tray and goes down to the next tray through a special down-comer arrangement

designing a tower that will do what you want is pretty complex

besides materials of construction and design configuration, you need to know reboiler capacities, cooler capacities, pressure requirements, rate, etc

and the mass transfer has to be modeled so that you will get a tower that will separate to the purity you need

good luck