Seems like there is a general consensus of centrifuge superiority in terms of solvent recovery (post cold EtOH extraction). Just received Capna Fabrications’ virtual demo and they use a vacuum type system with a 20-micron filter to rid the material of solvent (same idea as a Buchner funnel). Wondering if anyone has experience with this type of solvent recovery method or if it is truly worth it to invest in centrifuge set up.
Much appreciated!
Vacuum distillation (ie adding a condenser) might get the solvent back, but just pulling the liquid through using a vacuum doesn’t seem like it will get you much past the ~90% recovery drip dry gets you.
In my experience, for vac to work, you need a cohesive body of liquid solvent, once that has pulled through the biomass, you’re just running atmosphere past the solvent and evaporating it. I was using 15gal kegs in this manner. I had to let them drip dry after using vac to get the bulk of the solvent.
a centrifuge is drip dry on steroids…by spinning the biomass you can achieve the equivalent of 1000x gravity.
Gotcha, thanks for the insight! And yeah solvent + oil recovery is what I meant.
But 90% doesn’t sound that bad if we’re not in the market for a pricey centrifuge. Have heard of jerry-rigged washing machines being an option… Not sure how safe though.
heard of? Go read…
…and then do the math on going from 90% solvent recovery to 95% or 98% at your current (or desired) throughput so you can figure out the payback time in reduced solvent cost on the various options.
Edit: asking capna what their actual recovery is wouldn’t hurt. Understand that the solvent you lose to the biomass also has cannabinoids in it.
Capna states 80% recovery without a dewatering step. That’s a lot of loss just in EtOH cost alone if you’re running a substantial volume.
Thank you @cannabuilder!
If I’m honest with myself, 80% sounds about right based on my experience using vacuum. I didn’t do it that way for long enough to get solid numbers, but I do recall getting that number and having to immediately figure out a solution.
I implemented a 3 day covered drip dry to get to ~90% & tried a couple of other routes to get more before settling on the Delta-Separations unit.
I still haven’t gotten to really play with it.
I’m at 4hrs & in a holding pattern awaiting permitting.
If you vacuum distill the ethanol off you can get 90%+ back. Just depends on how far you want to take it. If you vacuum distill with 200 proof hardly anything is left. If you vacuum distill then run heated gas through it then you can recover basically 98%+
Getting the solvent that spins out is easy. Getting the last 2-3% is nearly impossible. Take into account the $/hr compared to $ saved by recovery. There’s certainly a point of diminishing returns and a cross over into unprofitable territory . The solvent is like $10/gal guys how much are you really saving?
if you’ve willing to pay for ethanol made from organically sourced biomass, you’re looking at closer to $70 a gal. depends what your customers want and how you got where you are.
Gotcha. I guess my OP was a bit misleading. I’m asking about the solvent + oil recovery from the extracted biomass. i.e. how “dry” I can get my stuff before sending the solvent+oil mixture to the rotovap, but that is good to know. You think 200 proof is worth it?
@Badger, the two suggestions for vac disitillation were both targeted at getting the little bit of solvent (~5%ish) left once you’ve got as much of the tincture (solvent + oil) as you can off your material . that solvent costs money. depending on how much you pay for solvent, it may or may not be worth going after that last little bit. eg drinkable, organic, denatured…