looking at Ethanol recovery options.
Falling Film seems to be the current state of the art. How does Wiped Film stack up?
Does anyone have data on using their WFE for solvent recovery? Or is it simply the wrong tool?
ive heard of people using wfe for a pseudo steam-hydrodistillation to strip terpenes and other volatiles so i dont see why it could be used for ethanol recovery. Im experimenting with inert gas stripping the ethanolic extract.
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For inert gas stripping, the depth of the film you’re bubbling through is critical yes? 3mm is the number I have. probably depends on the size of the bubbles.
At what point does the tincture become too viscous to bubble through?
25% cannabinoids?
Does Falling Film have similar issues as viscosity builds?
I’ve considered adding a spray ball and pump to my 26gal vac assist recovery still to see if I can speed things up, but I imagine it would have to be turned off at some point in the run & haven’t figured out how to make that happen in an operator independent manner yet.
Although just placing the pump inlet high enough in the vessel would work if the pump can handle running dry.
POPE certainly seem to think such usage is appropriate…
Versatility is also part of the package...The external condenser can also be utilized to provide the user with a continuous solvent evaporation system, substituting for a rotary evaporator...
if nobody else has tried it, I guess I’ll have to investigate it myself and report back.
don’t hold your breath though…I haven’t pushed go on the POPE yet.
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I was thinking of using a jacketed 4 inch sanitary spool vessel so I could warm it up and pull a partial vacuum then just use hot n2 to push it over the edge. One of the papers i have talks about optimal bubble size and depth but I don’t think it will be directly applicable to what I am trying to do
I think if warmed viscosity won’t be that restrictive. I know I’ll hav to finish purging separately but if I can pull the terps and the majority of the ethanol I think it will be worth
ive been looking into falling film evaporators and there is actually a middle ground between inert gas stripping and falling film
spritz and blow. while sucking. Hmmm…
and it involves Alcohol and Cannabinoids?
sounds like a win to me 
using an off the shelf sparging wand?
https://www.glaciertanks.com/tank-carbonation-stones-cbst-400.html
the falling film -inert gas hybrid i saw was just a bunch of vertical narrow pipes sized and designed so liquid runs down the sides of all of them while hot inert gas is used to heat the outside of the pipes or flowed “countercurrent” to the flow of ethanol
Toured Pope 2 day ago and their own people said Wiped Film wasn’t the proper technology for EtOH recovery. Their WFE is used for short path distillation of high molecular weight, heat sensitive molecules (ie cannabinoids). It will pull residual solvent on its first pass but this is solely to reduce the Psat of the mixture so they can pull a deeper vacuum necessary for the distillation of the real goodies. 20 second residence times are pretty impressive though.
Their 2" unit is ~$40k with everything needed and works through 250-500mL/hr of crude. Obviously this would be higher if you were feeding it for solvent recovery but I still believe it’d be quite a bit slower than a comparably priced FFE.
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Run one of these. Clean up your ETOH too. Dont think single plate barber poles are good for that. B/R runs these packed columns with and without vacuum. Claim no degredation. I want to see. I’ll be running one soon and can report results.20181014_165300|375x500
still would be faster than a rotovap though
Wiped film works greats for a couple of reasons.
- It is 1000% easier to clean and shut down vs falling film
- More precise temp and vacuum control
The only downside to WFE for most is surface area. Of course will all the little tubes in a falling film there is more surface area as compared to just the inside of the shell for WFE. My choice is WFE.
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