Hello nice people!Fractional distillation
is accomplished by varied apparatus:http://en.wikipedia.org/wiki/Fractional_distillationhttp://en.wikipedia.org/wiki/Spinning_conehttp://www.solvent--recycling.com/spinning_band_packed_column.html
but I haven't seen precisely the one I imagine, sketch below
(if you're logged in):
The rotating disks
expose a good area of liquid film for evaporation and condensation, while the pools are separated excepted for narrow pipes that avoid diffusion. This permits one temperature per pool and disk, and hundreds of disks
The rotation axis is essentially horizontal; a slight tilt can let the liquid flow gently in the direction opposite to the vapour, possibly with active valves at the pipes - or use pumps.
Limited clearances between the disks and the upper part of the vessel shall minimize vapour diffusion between the stages - use labyrinths or even seals if you prefer. Active valves at the liquid can regulate to zero the pressure differences between the stages.
The vessel can resist over- or under-pressure. Adding a carrier gas
to the vapour would allow the liquid to evaporate gently
, without bubbles: this makes evaporation more selective
. The disks can be corrugated or sintered for increased area. The apparatus can have several feeds and exits as usual.
What uses? I expect the rotating disks to evaporate and condense the compounds less quickly than other methods do, but:
- The gentle process, without spat nor local pressure and temperature fluctuations, keeps the evaporation selectivity
- Hundreds of disks cumulate their selectivity
- The process wastes very little power
(one evaporation heat for hundreds of repeated steps) so it can be upscaled;
- The horizontal axis eases upscaling as well.
Hence I hope distillation by rotating disks may find some use where compounds are difficult to separate.
Your opinion please? Is the Schaefer distillation
cr*p? Or exists already? Useless? Or maybe useful in some rare cases?
Marc Schaefer, aka Enthalpy