I think this is my first original post…can’t remember…
At any rate, I’ve been working with a chemical engineer (shoutout to Gokberk for all his help in generating this!) to develop a PFD (process flow diagram) of what a semi-continuous cryogenic ethanol extraction lab would look like.
I say semi-continuous because the plant material input it batch. Everything else is written as continuous flow (even the carbon filtering!).
A couple of points before we get started:
I know there are other ways to extract/filter/distill, not everyone likes ethanol
I plan to create more of these documents for other types of extraction in the future (butane, propane, CO2, etc).
It is possible to create beautiful, water-clear distillate without carbon washing or bleaching. I am merely illustrating a very popular method for clarifying.
This model is meant to illustrate a very popular, scalable method of extraction to distillation, NOT to say this is the “Best” way to do things.
I chose to mark the ethanol from de-solvation as “Waste” due to the cumbersome task of integrating a fractional distillation recovery system in the current market.
This is a QUALITATIVE PFD. That means it doesn’t have all the nitty gritty for a proper simulation. Quantitative to come!
I hope we’ll get some constructive feedback on the PFD and suggestions for improvement.
couple notes
-removing all particulate and semi-solubles is important for max decolorization efficiency, normally at least. Im sure you meant it, but I would put a secondary separation step between 1 and 2
-Holding vessels in between each step
-Bulk evaporation isnt limited to falling film. (splitting hairs I know)
-Secondary solvent stripping step, bulk evaps more fun when you can run it quicker and have a secondary device to pull lasting solvent
-post distillation procedures eg. liquid separation, filtration, decoloraization
This looks very similar to mine, only much more detailed and well laid out - mine stops at basically the evaporation step as everything after that is designed to be a separate process in our setup.
Decolorization shouldn’t really be necessary with -86 EtOH? Though filtration of some form will likely be necessary.
I like the LN2 cooling vs the chiller/heat exchanger setup we’re currently planning on using. Much simpler, all things considered.
@Psilisophical has a good point with the holding tanks (and everything else), that’s something I’ve missed in mine as well.
Looks like my diagrams but mine have valves, spec reference sheets, and all the other little details that are needed to actually piece out a build.
Then again I charge anywhere from $350-500/hr per consult and almost always require either some equity deal or advisor role.
These PFD’s are often borderline P&ID’s and play hand in hand with laying out large process scale facilities. With most jurisdictions requiring closed systems, it is becoming more and more common that I have to develop diagrams for fire marshals, for my various clients CUP and final planning phases.
Looks good to me, somewhat vague, but nicely laid out, though!
@Cannachem This is a qualitative PFD. We are planning a quantitative one as well. Our hourly rate starts at $700 for the first hour followed by $500 for each remaining hour. I will add that to the preliminary comments thank you!
Thanks you brought some points I was musing on last night…especially about the holding tanks.
I think I’ll add holding tanks between all the steps, but for between falling film and de-solvation, add a stirred holding tank (jacketed heated) to aid in the degassing and decarb. What do you think?
Bulk evaporation- any other suggestions? Falling film seems to be very popular these days. Ace has ideas for a super sonic “spray-vap” (but not spray vap) style insta-desolve…
Secondary solvent- So did you mean something prior to the first stage of the triple-distillation?
Yeah I definitely need a decarb tank in there; I’ve used falling film, desolve—>terp strip passes to decarb before and its been alright, but I think (theres some math to be had here)…some things to consider are:
Is the residence time in the falling film, 1st stage of distillation (volatile), and terp strip, enough to decarb fully and if SO… is that time shorter than a holding tank that is stirred under vacuum with heat?
Or perhaps the falling film ----> stirred reactor can decarb and take care of residual solvents at the same time? There would be a huge gas load and it would take “longer” however it wouldn’t be moving from tank to tank. I like the idea of desolvating on a thin film to avoid pockets that get “stuck,” if you will.
@Lilibel
As @Cannachem mentioned, it probably looks like many of our initial PFD’s. I recommend including the heating and cooling loops as well - though it makes it tougher on the eye to look at. A lot of people will totally forget you need hot/cold sources no matter how many times you verbally mentioned it. This PFD might lead someone to believe that all the major components are accounted for - though none of the heaters/chillers are represented (besides the initial LN2).
@Psilisophical
Agreed. I am working on a buildout right now that is likely incorporating more rising film evaporation than falling film. I think rising film will have better thermal transfer, but with slightly slower flow rates - given that all other factors of heat exchange remain the same. In other words - it will cost less but will take longer to operate per volume of solution.
Hi @Lilibel, this is a great PFD. I know this is from ProII Simsci simulator. I’m trying to simulated the process. I made the molecules of cannabinoids by using unifac structure. But to get a better simulation I wanna khow if you simulated the whole plant. Also, I have the kinetics of the descarb to put it in a reactor.
