well you do hang out in a blog that has not kicked me out yet… or a pub… or a school… or a federal building… or a family branch… or my apartment…
But that won’t count against your score too much 
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@TheGratefulPhil do you see any uses for Fractional Distillation towers in the cannabis market? My theory on why we don’t see these is that the various boiling points for extracts are too far apart. Thank you for being gracious with your sick skills.
Its the opposite the BP are to close to each other. This is the reason we don’t have one in the industry. Nobody has designed a column that can have precision parameter control of the process.
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@Juice311 is correct. Relative boiling points are extremely close. Moreover, when you have complex mixtures (in the case of cannabis extract, 100s of compounds) the design of fractional distillation towers becomes extremely difficult.
I think as the industry gains more expertise, this becomes a more feasible prospect—after all, if they can do it with petroleum, why not cannabis?
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Nice thread,
I have been confronting some of these issues on my instagram feed, from two generally simpler perspectives. I was considering making a thread about this but you beat me to it.
This is what I have been using:
- Choked flow theory(Choked flow - Wikipedia) for gas flows to estimate the maximum possible flow through a pipe, currently I have charts posted for butane flows
a. Mass flow rate is very dependant on the upstream pressure and temperature
b. Charts could be redone for ethanol vapor - Energy balance from enthalpy of vaporization of the solvent and refrigeration system power.
a. Shows recovery rates possible under ideal parameters with no pumping loss etc. for 2.5, 4 and 15 ton systems. - Specific heat transfer models for the heat exchangers I have not done, as our vendors have simulation codes far more accurate than my hand(excel) calculations.
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im thinking the next few years we will see one out on the market. Once federal it will be on the market. This wouldn’t be hard fir a engineering firm to design. This would be a child’s toy compared to the refinery sized towers.
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Also account ambient temperatures bridging on your equipment.
Your also not accounting, type of piping/hosing and each angle or bend in your lines.
I’m betting the butane calculation are a straight line on the excel.
Degradation is always the limiting factor
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Yep i can’t Believe i forgot about that factor. I know efficient fraction towers use turnaround pumps to keep its self controlled.
I would imagine the system would need to be automated with a plc control board. Possibly a DCS if it’s that complex. operator error would be to costly with no pre training/schooling.
@Juice311 and @TheGratefulPhil, thanks for the clarification. Any rule of thumb on what the temperature gradient should be between extracts on a traditional fractional distillation tower?
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Honestly, I’d assume it’s more about the capacity of the tower for vacuum and this ability to drive vapor flow with a relatively low bottoms temperature.
I’ve thought, in fact that it may be helpful to use the reflux from a condenser to cool bottoms before they’re recycled into the column.
As someone mentioned, degradation is a very real issue in terms of limiting distillation. Molecules of interest can have BPs between 30 - 200C depending on vacuum depth—it is critical to reduce the residence time of the mixture in the higher range of these temperatures, i.e. it is desirable to reduce the residence time of the mixture in the 170-180C range.
I think that this process is not nearly as feasible as a distillation column for oil, not least because we have a tiny fraction of the data we need to even begin experimental design!
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They will def have a sweet spot with vacuum depths. Like you’re saying to low it will degrade rapidly vs atmospheric distillation higher temperature degrading. Every crude batch would need an analysis stating each cannabinol and than adjust parameters fir effective isolation.
I know vacuum equipment is consider a novelty item in the petro world. It’s very expensive for large production and in hindsight there is less data.
I’ve thought about how to design one last year but this is one of those projects you would have to go flush to figure out and possibly go a bit insane to create it.
flashing is the biggest hurdle to figure out under under vacuum fracking.
Selective evaporation—pervaporation is a good place to look—not exactly distillation column’s, but could have utility in using vacuum and lower temperatures
Sorta like a flash drum/ knockout drum? I know they use these more in processing in the current age unlike older times it was used before a flare.
@TheGratefulPhil what does this mean?
If this is true I wonder if it would be worthwhile for the Future community to design one like @Future started for his distillation project. Maybe we pioneer something truly revolutionary as a group?
Cannabinoids fall apart under heat.
They degrade/oxidize/isomerize.
If your benzene falls apart and you get hexenes in your petrochemical distillation tower, it’s all good, it just goes in a different bucket. Here, accidentally cracking your input is frowned upon
Edit: apologies to the chemists in the room…at least it’s the right number of carbons 
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If I understand the theory we are circulating here the idea would be to sequentially separate each product starting with lower temp stuff first and evaporating at each stage at a higher and higher temperature. Almost like a fractional distillation tower working in reverse order. In theory each stage would strip off a different product. Or could you do it with Wiped Film Distillation chambers in series? @cyclopath your point that a fractional distillation tower would not work because all product would have to start off at the highest temp which would degrade/oxidize/isomerize makes a lot of sense.
(video on Pervaporation)
This is exactly what I meant about degradation, although if one were to explore this technology, this would certainly one of the primary issues to address
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