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Supercritical CO2 for the Entheogenic Hobbyist

Migrated topic.
BongWizard said:
... the co2 will lose energy through The Joule-Thompson effect as it passes through the valves, causing it to be sub-critical by the time it enters the extraction vessel.
Click to expand...
Yes the extraction vessel might have a lower start temperature being on pressure, but with how much? Letting it warm up to room temp might be enough to compensate. No? just thinking loud. It's all pretty adiabatic during the pressurization of the extraction vessel, but not afterwards, it can take energy from surrounding (heat up again) just on itself being in the room temp. A heat pad can only speed this up. True.

The price of the RV is a real bummer :x
Didn't know of prices.
Things are really going to depend on the manometer, a redundant second one for safety instead of a PRV then?
 
benzyme said:
... now you have me thinking about insulating the valves..
Click to expand...
Why?
They are going to be cold, and that is what we want to avoid, no?
I would let them warm up again to room temp, to get back direction super critical, insulation would slow that.
Once the cold is gone, there's going to be super critical again I suppose.
Just some thinking.

PS, what is the reason for the 1400 - 1500 psi target? Is it not possible to let the extraction float on the storage vessel's 1800 psi?
 
benzyme said:
you know what, that's a good point...
but the heat pad around the storage tank is what's driving the direction of flow. now you have me thinking about insulating the valves..

the heat pad around the extraction vessel is the second phase of transfer, to the collection vessel.


Jees, I've decided to wing it.. they want $480 for that damn PRV :shock:
Click to expand...

Shouldn't the flow be driven by the excess pressure in the co2 source tank?

You should be able to fill the extraction vessel to a low operating pressure (say, 1200psi) close the in valve and apply heat (keep an eye on the pressure, obviously).

$480 for a relief valve!?! That's unreal! And not in a good way.

Have a look at this one (1/2 NPT 16 GPM 1000-2500 PSI Relief Valve Prince Mfg RD-1850-H 9-1556 | eBay ). I know it's not technically a gas fitting but, in my experience, hydraulic fittings work well for high pressure gasses as well. And for less the 10% of the outlay, how can you argue?
 
BongWizard said:
Shouldn't the flow be driven by the excess pressure in the co2 source tank?

You should be able to fill the extraction vessel to a low operating pressure (say, 1200psi) close the in valve and apply heat (keep an eye on the pressure, obviously).
Click to expand...


doing exactly that, as I type.
Pressure is steady @ 1350 psi, temp 40-44C. no leaks.

extracting from finely ground toasted pecans.

the valves and sample cylinder are warm to the touch; but obviously, the sample cylinder is colder than the storage tank, dictating the direction of flow.
 

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Successful run and a healthy yield. Nice work benzyme.

It might be worthwhile to insulate the extraction vessel and hoses/fittings leading up to it. I doubt it would improve performance, but it should help with energy efficiency in the long run.
 
thanks, I totally hear ya.
witnessed the Joule-Thompson effect, which I knew would happen before you mentioned it. This is P.Chem in action, a refresher from a class taken ten years ago... SFE isn't covered in any p.chem lab though. never tried this method before...

so now, I have at my disposal:

Solid-Liquid Extraction
Continuous Liquid-Liquid Extraction
Ultrasound-Assisted Extraction
Microwave-Assisted Extraction
and Supercritical Fluid Extraction
 
parts list:
(all brass or stainless steel, except storage tank, and all rated for 3000psi, unless specified)

CO2 storage cylinder
1 10lb aluminum CO2 tank, rated @1800psi
1 CGA-320 cap and stem, with nylon disc (usually included)

3 Swagelok QF-4-S-4PF, quick connect stems, one connects to CGA-320 stem on storage tank, other two connect to needle valves on the sample cylinder

Sample Cylinder
1 Swagelok Whitey 1000CC sample cylinder, with two 1/4" FNPT ends, rated for 1800psi
2 Swagelok 1/4" MNPT needle valves, rated for 6000psi
400mesh SS screen, cut a small piece to stuff in needle valve on sample cylinder outlet

transfer hose assembly
2 Swagelok SS-QF4-B-4PF
2 Swagelok tees 1/4" FNPT
1 3000psi oil-filled pressure gauge, 1/4" MNPT
1 60" stainless steel braided, PTFE-lined hose with 1/4" MNPT ends
2 Swagelok needle valves, 1/4" MNPT, rated for 6000psi, one connects to tee connecting to sample cylinder, facing out..this will be for bleeding backpressure, to disconnect the transfer line
2 1/4" MNPT unions
1 1/4" hex FNPT union

collection vessel, low pressure

3" x 12" sanitary stainless steel spool
1 3" triclover endcap
1 3" triclover endcap with two 1/4" FNPT inlets, or one with 1/2" (then also get a 1/2" to 1/4" FNPT bushing)
2 3" viton gaskets
2 3" triclover clamps
(connects to collection vessel inlet) 1 Swagelok QF-4-S-4PM
1 1/4" MNPT pressure relief valve, 140 psi

heating assembly
1 silicone heating pad, Omega part# SSHB-1224-720-120
1 PID temp controller, Mypin TA-4, with thermocouple
1 20A relay

note: remember to wrap PTFE tape around all brass-brass/brass-ss/ss-ss connections, 3 rounds. hand tighten connections as much as possible, mark across the connection with a permanent marker, then wrench tighten 1 1/4 turns (for 1/4" NPT connections, as specified by Swagelok).
 
benzyme said:
so now, I have at my disposal:

Solid-Liquid Extraction
Continuous Liquid-Liquid Extraction
Ultrasound-Assisted Extraction
Microwave-Assisted Extraction
and Supercritical Fluid Extraction
Click to expand...

Quit bragging! Lol 😁

I'd love to get myself a sonicator, but I just can't justify it atm
 
That's my thinking. I love purified psilocin , but cooking the mushies properly is rather time consuming. A good sonicator would let me rip through em.
 
Thank you B for showing the way. And congrats.

Was that 1 pull, like once pressurizing-depressurization of the extraction vessel?
How long was the pressure on the material?
 
1 extraction cycle of about 4 hours using supercritical co2 and denatured alcohol, if I'm not mistaken (though this question is really benzyme's to answer)
 
benzyme said:
ok...it's holding steady between 1450-1500psi, @ 43-44C, after 2 hrs...
Click to expand...
Ok I see the 2 hours remark here. 4 wouldn't hurt I suppose.

Is there a special reason (besides price) about the alkohol being denaturated?
 
I imagine price is the only consideration here. Although I make my own 100% ethanol for about $1.50 per L, less than half the price of denat. here in oz
 
denatured alk is cheaper than everclear, and is only used to rinse the line and vessel. it is boiled off in a water bath.
although, there may have been residual alcohol in the vessel, i rinsed it prior to extracting.
(for alks, it would behoove one to let the dry plant material soak in alcohol (with very little water content) in the sample cylinder, before flooding it with SC-CO2).

I washed out all the raw material from the sample cylinder with tap water, then rinsed with acetone.
the pecan pieces still had waxes, but were mostly dry. only one pull was done, approx. 2hr. 50min @1350-1500psi, 40-44C.

this weekend, I will try theobromine from cocoa nibs.
 
Hieronymous said:
ouro said:
cool idea -

to extract freebases you would need to wet the material with base first, then dry, no?

Also, how do you know alkaloids are the main substance soluble in super critical co2? It seems like a good solvent for many things in plant material.

viewing window? I'd be more inclined to automate it as much as possible and bury the device in cinderblocks/bricks/sandbags while its under pressure.
Click to expand...

I'd expect raw plant matter to contain alkaloids in their salt form so basifying would have to be done at some stage. Basifying before the extraction would most likely be the best route as it should eliminate the need for hydrocarbon solvents. That being said there are options for basifying after the extract.

I can't say for sure what the CO2 will extract, there isn't a great deal of freely available information on the topic in regards to what is soluble in SC CO2. My preliminary investigations seem to indicate that non polar molecules are soluble in th SC CO2 so I'm hoping it will be a similar profile to a xylene extract.

It could be more selective I just don't know. Maybe some of our chemists could help here ?

A sight glass rated for boilers/steam should take the pressure, but I tend to agree with you and would most likely omit that from my prototype. I don't know what would be so important that it would need to visually monitored anyway. I'd prefer to monitor the process with thermocouples and pressure gauges.

I was thinking of the safety of the operational procedure for the device too, I certainly wouldn't want to be near something like that in the event of rupture/failure.

Any pressurised gas has the potential to kill. I know a small leak in a dry/superheated steam system can easily cut a man in half. So to run such a device it will certainly need to be safely contained in something resembling a blastproof cabinet or buried. The device will also have to be designed to be fail safe (if it fails it will fail safely) and have an excessive safety factor carefully calculated in the design phase.

This type of device is beyond the scope of your neighborhood plumber or backyard mechanic and I wouldn't consider building this without consultation from an engineer with hands on experience in high pressure applications.

Don't try this at home kids.
Click to expand...

I went back and read this post to address some questions..
I've done a bit of reading on this method, and have found that SC-CO2 has similar polarity to hexane. although, because of its quadrupole character, it may pull slightly polar molecules. this is enhanced even more with the addition of alcohols.
SC-CO2 is mainly effective in pulling small molecules, <300 m.w., and somewhat effective at up to 500m.w. or so, with high pressure (>200bar). at 188m.w. , DMT falls well within these limits, a basification of the plant material, and drying would be a practical approach. fats and tannins would be excluded at lower pressures in the supercritical regime (100bar)
(salts are not good candidates for this method, unless you're looking to recrystallize them).
 
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