Heated Gas Extraction

BobCajun

Well-Known Member
I found a cool new way to make extracts without solvent. Instead, you use hot gas, either nitrogen or steam. This is a lot easier than CO2 extraction because no pressure involved and produces a higher potency product, almost pure THC actually, see table below. It's basically like short path distillation of THC but you can start with plant material directly instead of going to all the trouble of extracting with solvent or CO2 first. See patent for details. Only problem is heating the gas to 130-175 C to vaporize the THC, but still heating is easier than pressurizing.

 
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BobCajun

Well-Known Member
Looks like you can just use hot air, might be a little CBN formed though. Maybe you could use an adjustable heat gun as the hot air source. I guess you'd have to insulate the path between the heat gun and the condenser somehow. If a practical setup can be made fairly simply this could be even better than rosin, less secondary crud in it and almost as simple.

"[0117] The following studies were carried out using a pilot-scale version of the apparatus of Fig.1. The apparatus can be run continuously and accepts a charge of 50g botanical raw material, which is heated for approximately 15 mins.
[0118] The starting botanical raw material was a high THC cannabis chemovar (designated G1) containing more than 95% of total cannabinoid as THC and its precursors. Extraction was carried out by contacting the botanical raw material with forced hot air flow at various selected temperatures. An inert atmosphere of nitrogen could be substituted for the flow of air, for example to prevent oxidation of the cannabinoid component THC to CBN. Volatilised components were condensed by means of a "cold finger" filled with a salt/ice freezing mixture"
 
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Fadedawg

Well-Known Member
I'm working on a variation of that principle, but running the vapor stream through an +27K volts electrified anode grid and collecting it by then passing it through a -27K volt cathode tube. I can crank it up to about 80K volts, but it will arc an inch per 1K volts, and I only have 6" borosilicate insulator tubes, limiting me to about 50K.

Eloquentsolution and I did the preliminary run, which worked, but I'm going to a longer cathode tube, because it didn't capture 100% of the discharge from our Volcano.
 

BobCajun

Well-Known Member
I'm working on a variation of that principle, but running the vapor stream through an +27K volts electrified anode grid and collecting it by then passing it through a -27K volt cathode tube. I can crank it up to about 80K volts, but it will arc an inch per 1K volts, and I only have 6" borosilicate insulator tubes, limiting me to about 50K.

Eloquentsolution and I did the preliminary run, which worked, but I'm going to a longer cathode tube, because it didn't capture 100% of the discharge from our Volcano.
I did read that electrostatic collectors can be used to harvest droplets after the gas stream is cooled enough. But all that is beyond the average person's practical use, so I'm thinking a metal tube in which you load plant matter, with screens on both ends, attached to a heat gun on one end and a long glass or metal tube on the other end, cooled by probably just a fan blowing on it. That would be positioned vertical above a collecting pan.

A heat gun is fairly low flow rate so it's likely that all or most vapor would condense before reaching the end of the tube. It's not water cooled because you want it to stay about 50 C so the oil will drip out. So this would be similar in appearance to blasting BHO but using hot air instead of butane. If the tube was flattened somewhat, like a vacuum cleaner nozzle, more gas would contact it to condense more than with a round tube.

BTW, that table I posted is for when steam is used as the gas. With hot air it's about 70%, so similar to BHO.
 

BobCajun

Well-Known Member
Looks like it has possibilities, just have to let the steam cool to about 150 before it reaches the material, because the page says 210-220. So you would just need a bit more tubing before the weed chamber. An IR thermometer would show how much tube would be needed. It might be okay as is, but could produce more CBN.

With steam, the distillate would probably come out of the condensing tube better than with dry air, be washed out.
 

BobCajun

Well-Known Member
Actually I read the manual and it's F temperature. It only gets to 250 F max. You need more like 300. Normal steam would only get the terpenes I think, like normal steam distillation. Back to the heat gun I guess.
 

BobCajun

Well-Known Member
Speaking of heat guns, odd that nobody thought of using one instead of a torch for heating up a dabbing nail. A lot more precise temperature control and no open flame to cause a fire.
 

Fadedawg

Well-Known Member
I did read that electrostatic collectors can be used to harvest droplets after the gas stream is cooled enough. But all that is beyond the average person's practical use, so I'm thinking a metal tube in which you load plant matter, with screens on both ends, attached to a heat gun on one end and a long glass or metal tube on the other end, cooled by probably just a fan blowing on it. That would be positioned vertical above a collecting pan.

A heat gun is fairly low flow rate so it's likely that all or most vapor would condense before reaching the end of the tube. It's not water cooled because you want it to stay about 50 C so the oil will drip out. So this would be similar in appearance to blasting BHO but using hot air instead of butane. If the tube was flattened somewhat, like a vacuum cleaner nozzle, more gas would contact it to condense more than with a round tube.

BTW, that table I posted is for when steam is used as the gas. With hot air it's about 70%, so similar to BHO.
Here is my hot air conceptual that I never built. It uses both an outside chilled jacket and a cold finger at -40C.

I started experimenting with electrostatic precipitation because of the high cost of coolers. Radar Bob built my 27K VDC power supply for $150. It is also easier to harvest.
 

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BobCajun

Well-Known Member
Here is my hot air conceptual that I never built. It uses both an outside chilled jacket and a cold finger at -40C.

I started experimenting with electrostatic precipitation because of the high cost of coolers. Radar Bob built my 27K VDC power supply for $150. It is also easier to harvest.
Well if electrostatic works better than cooling then that would certainly simplify things, if one could get such an item. The Vapenator eh? So I guess I'm a little behind on this hot gas extraction thing. But then I do find most stuff in patents so they've ALL been discovered before. I do appreciate those people doing all the grunt work though.

BTW, something else I was thinking about is using a thermoelectric peltier cooler. You could put parchment or something over the cold side of the plate and condense it right on the parchment by having the air stream blow directly on it. Hopefully not much water would also condense with it, from the air humidity. Maybe a finned heat sink with the parchment folded like an accordion to fit over it. You could keep selling the specially prepared parchment to buyers.
 
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Fadedawg

Well-Known Member
Well if electrostatic works better than cooling then that would certainly simplify things, if one could get such an item. The Vapenator eh? So I guess I'm a little behind on this hot gas extraction thing. But then I do find most stuff in patents so they've ALL been discovered before. I do appreciate those people doing all the grunt work though.

BTW, something else I was thinking about is using a thermoelectric peltier cooler. You could put parchment or something over the cold side of the plate and condense it right on the parchment by having the air stream blow directly on it. Hopefully not much water would also condense with it, from the air humidity. Maybe a finned heat sink with the parchment folded like an accordion to fit over it. You could keep selling the specially prepared parchment to buyers.
Hee, hee, hee, looks like a fun project!
 
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