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Supercritical CO2 for the Entheogenic Hobbyist

Migrated topic.
I have good experience with supercritical CO2, its awesome because of its polarity being so low. But with it the troubles I have also outlined in the general extraction thread come:
With the setup I build myself long ago I can not run a continous extraction (like most MJ people would do with butane) so since a while I am considering either using butane of evaluating a circulating CO2 system with a choke. a compressor and a heating element.
I highly recommend TIG welding a extraction chamber from stainless steel (and not bother about "being able to see in there or you learn the hard way that supercritical CO2 can creep into acrylic ;) ) and heat it on a lab style heater. Thats a simple setup and does the job for non-continous extraction, meaning you add everything to your reaction chamber, your plant matter and your CO2 from a siphoned bottle ( or turn your bottle upside down :/ ) and the correct amount of heat and let that sit. This process does leave desired goods in your plant material, since the concentration in your chamber will be the same everywhere, in your solvent and your plant matter. Continous Extraction would help with this issue, the device sketched above would also cut down on CO2 use by recycling. I have just not yet found if the supercritical state might do something I do not expect when the CO2 encounters a choke like those in traditional cooling systems.

Hieronymous, if you really want to make use of the lathe (sawing of heavy stainless tubing and welding it shut on both ends does the job lathe free) and youre concerned about the pressures and forces involved, spin yourself two half spheres of tough stainless and you'll be able to wels yourself a spherical chamber that fits into a round bottom flask heater and is, because of its shape, the thoughest you can go.

I would highly recommend to go for it, just for the experience :) I must admit personally I've come to mostly simply use the Soxhlet apparatus with methanol, no trouble, good yields, ease of opperation, I've even stopped using the glass or cellulose containers that go inside and simply stuff it with somw cotton at the base and top, works :)
 

this describes a simple detailed open-loop setup (closed-loop systems recycle the CO2, but are more complicated, and thus, more expensive), based on what JYN had experimented with and found to work. I've ordered all the parts listed for the transfer assembly, and a 20# beverage tank. If anyone is interested in building a similar app, be mindful of the max. pressure ratings for all components. 1/4" i.d. fittings described in the link have a max. pressure rating of 3000psi
 
Benzyme- Im very interested in this and will be watching your progress. Im currently travelling, but I should be settling down somewhere in about a month and a half and I will begin sourcing this project myself.

General ballpark on how much of an investment this is going to be? -or, so far haha- I know this sort of thing ends up being much more expensive than initially planned, specially when youre groping in the dark.

I reached out to jyndustriez to pick his brain but his site has been taken down, along with email. Also tried reaching out to him through other means with no response :/
 
I've tried reaching out to him with the same result.
Right now, I have this on the back burner temporarily. Floods have affected surrounding areas, and have me working weekends because of it.

I have all the fittings necessary to do this, just waiting on some collection tanks from a friend, and I need to buy a heating pad. I will post a detailed parts list. Fittings run anywhere from $5-50 on e.bay, generally. You're looking at an investment of $400-700, using the CO2 cylinder apparatus. most of this cost will be from cylinders, heating pad, and a pressure vessel, if you opt to use one. Some have claimed to use a <$100 setup with dry ice and a dewar vessel, but I'm skeptical in its ability to actually deliver CO2 in a supercritical state. all points need to handle a minimum of 1073 psi @ 31C.

get stainless braided hoses and fittings, whenever possible, or brass.
I buy Swagelok, because I am familiar with that brand. quality stuff..not cheap, but very dependable. Parker, Whitey, and Cajon are also good.
 
Tri-Clamp® Spools for the product vessel
tri-clamps, endcaps, and viton gaskets of the same size are required. one of the endcaps should be like this

where one port is for line in (via bushing, 1/2" MNPT, 1/4" FNPT) and the other holds a pressure relief valve, like this

m.ebay.com

150 PSI BRASS SAFETY RELIEF POP OFF PRESSURE VALVE, COMPRESSOR, TANK, 1/4" NPT | eBay

Conrader safety valves are designed to protect unfired pressure vessels and systems from over pressure in compressed air and gas applications. 1/4" SAFETY RELIEF VALVE (POP OFF VALVE). Including, but not limited to, using alternative products.
m.ebay.com
 
Explain to me why the gauges are in the same pressure cell. Are they different ranges? Wouldn't it be more useful to have one between the transfer tank and it's needle valve. If I were setting this up, I would go something like this

(CO2 source)->(needle valve)->(gauge)------>(needle valve)->(gauge)->(solvent junction)->(handscrew fitting)->(transfer tank)

And to introduce the entrainer

(Reservoir)--->(solvent pump)----->(hand valve)->(solvent junction)

The only reason I include a manual ball valve instead of a spring loaded check valve is that I've had bad experiences with check valves and solid-liquid suspensions. If they get gummed up and you can't see it, you can end up ruining your pump.

I'm assuming you'll transfer the extract out the same port as where the handscrew fitting will go (otherwise why have a handscrew, right). This transfer will bring a lot of plant material with it, correct? Will there be a filter inline or is that built into your stainless collection tank?
 
yes. didn't mention, there will be a 2 micron swagelok filter going into the collection vessel, and some stainless mesh in the transfer tank. you brought up an interesting scheme for the placement of the valves, I'll certainly give it some thought. nothing is concrete yet, except the heating assembly and collection vessel. not too worried about the check valve, but I would actually put it inline at the first needle valve, otherwise i suppose it could take the place of one of the gauges. polar solvent input is occurring through said check valve.
 
Ahhhh, alright I'm with you on the check valve now. It shouldn't have any junk going through it in that configuration and even if it does the CO2 pressure will blast it clean.

Yeah, with the gauges in the config as pictured they'd always read close to the same pressure. If you put the second one behind the needle valve you'll get an idea of how much your second needle valve is throttling the flow (should give better control).

Just as an idea, instead of the handscrew fitting, you could probably use hydraulic quick couplers for even greater ease of use.
 
I see now. Thought those were reducers. Probably won't find too many quick connects without safety stops these days. Do you think putting a T joint with a vertically oriented ball valve would be a viable option? You'd obviously want it as close to the transfer tank as possible. You could even use a couple of reducing sockets to make a sort of funnel for addition of material on top of this valve.
 
A control valve between the collection vessel and the blow off valve might be a good idea. Once the transfer begins, the 140psi vent pressure will be reached quite quickly, the extra valve will allow you to control the outflow rate. My reason for this suggestion is that the methanol (or other polar solvent) likely won't have separated from the CO2 and could end up being pushed out the vent.

I could be completely wrong, just a thought though.

IMO, more control points is better. If they're unnecessary, you can leave them open, but if you need them and they're not there, you could end up messing up your extraction.
 
So you're using the same line to do both transfers? Also, have you considered how you're going to clear that filter? I'm thinking it could get blocked pretty quickly, which isn't an issue at > 73 bar, but this pressure won't be constant
 
How are you going with your rig benzyme? Got it finished yet? I'm quite eager to see how well yours works because I'm considering throwing a similar setup together for experimentation with a bunch of different Aussie acacias and I need a good efficient extraction method.
 
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