5 replies to this topic

[chemsep05]

I would suggest a RDC (Rotating Disc Contactor) column, the diameter and height are related through several equations, usually a RDC will be fairly small in size, you may in most cases have to choose the height and diameter

[siretb]

A RDC (rotating disc contactor) is mostly used for Liquid Liquid extraction. I do not know the ammoxidation process for proplylene to acrylonitrile, but unless pressure is very high, the propylene is gaseous. So I would question the RDC choice.
So I would rather think that suitable technolgy would be a packed colmun, or a trayed column.
The choice between a trayed column and a packed column will depend upon many parameters, including
the absolute pressure you operate at, the L and V rates, .... and fouling tendency.
Packing is specially desirable if a low pressure drop is needed. Is that the case?
Packing works best at low flow parameters, and with non-fouling mixtures.
I hope this helps. If you need more, please por=st additional information (flows aroud the unit, esp.)

[siretb]

No, a packed column can be much much larger in diameter than 2ft. Of course, you need to select the proper packingb, but a few meters is no problem at all.

As for your diameter, 4.3m seems low to me, at least for V=8917kmols/hour and L=24571 kilomols/hour and 200 kPa. What vapour density do you use? What tray spacing do you use?

To account for the heat effect you'll need a thermodynamical model that does that. If they are very significant (regarding the heat capacity of the liquid flowing) you'll vaporize more.

[hana85]

Thank you. I have my data.

Gas flow rate = 8917kmol/h
Gas temp = 80 degress celcius
Liquid flow rate = 24751kmol/h
Liquid temp = 5 degrees celcius

Pressure used = 200kPa

I think my column needs to take into account heat effects as the system is non-isothermal
Please advice on how I can go about doing it.
The diameter was calculated to be about 4.3 m. I think it is too big for me to use a packed column as
according to industrial standards, the maximum diameter for a packed column is around 2 feet.
I hope my assumption is correct and a tray column is the reasonable choice.

how did u calculate the diameter using the data u have?