4 replies to this topic

i would like to ask why packing should be considered instead of tray column under vacuum condition?

[Art Montemayor]

Lemon:

A column working under a partial vacuum is very dependent on keeping the pressure drop across the column as low as possible. Packing has proven to give a lower pressure drop than tray construction - especially bubble caps.

[Zauberberg]

One additional comment, apart from correct Mr Montemayor's reply.

In vacuum applications, vapor volumetric flows are huge. If, instead of packing, the column is equipped with trays, you would need much larger cross sectional area in order to handle the same volumetric flow rate of vapor. This is because only 50-80% (depending on service and design criteria) of trayed tower cross-sectional area is provided for vapor flow. Therefore, if you solve liquid and vapor distribution issues immanent to packed towers, you will gain a substantial CAPEX savings when deciding to go for packed tower for your application.

Regards,

Thank you for information about this.
Appreciate it.

[riven]

In addition to the above:
www.graham-mfg.com/downloads/vacadem3.pdf

See page four. This shows why minimising pressure drop is important. High drops (regardless of where they are) will affect recovery and thus a much larger column is needed depending on circumstances.