Affordable DIY CO2 Extraction???

[vertigo0007]

Opaque yellow, not clear in any way, beyond cloudy. The oil that seperates is clear orange/red.

 

[Gray Wolf]

Well what do you know? I had a guy show me a quick video of a unit he is involved with using. It was a video of that first picture spewinf the extract out the tube into a jar. Its being made on a machine that supposedly is in a state inspected lab. Any idea what type of lab would have this machine amd allow its use for cannabis? I was thinking a struggling 'micro-brew' coffee company, or maybe a flavor extract company. Its a yellow goo that seperates an orange red oil as it sits. It smells and tastes like raisins and tests at 50%ish. It smells like ethanol extract i tried once, but looks completely different. Oh and it sparks and pops like hell when you put a flame to it. Is that the carrier solvent they claim they dont use and the local lab claims its certified free of? Give the some truth Lord Wolf

Good question! Popping and spitting is usually water, which ostensibly CO2 SFE would be free of, but maybe not.

I am due to conference with one of my best resources and will ask his thoughts.

 

[vertigo0007]

Thank you kindly sir

 

[maxrosen666]

I've also been building an SFE chamber. The chamber itself is finished and I have pressure tested it far into super critical phase, but now I'm running into the problem of separating the non-polar compounds out from the CO2. I've hit a wall as far as what this separator should look like, and how it should function.
My process:
1) Fill the chamber with plant matter.
2) Fill chamber with liquid CO2 at 1800 PSI at room temp.
3) Using strap heaters around the chamber, raise temp above 31 Deg Celsius.
4) Allow to stay in super critical phase for a minimum of 4 hours.
5) Allow temp to drop back down below super critical and back into liquid state.
6) Separate CO2 from non-polar compounds.... but how???

 

[Gray Wolf]

I've also been building an SFE chamber. The chamber itself is finished and I have pressure tested it far into super critical phase, but now I'm running into the problem of separating the non-polar compounds out from the CO2. I've hit a wall as far as what this separator should look like, and how it should function.
My process:
1) Fill the chamber with plant matter.
2) Fill chamber with liquid CO2 at 1800 PSI at room temp.
3) Using strap heaters around the chamber, raise temp above 31 Deg Celsius.
4) Allow to stay in super critical phase for a minimum of 4 hours.
5) Allow temp to drop back down below super critical and back into liquid state.
6) Separate CO2 from non-polar compounds.... but how???

Good for you! What are you using for a chamber?

 

[maxrosen666]

We deigned, simulated, machined, welded, and heat treated a structure from scratch, it's made of 6061 Aluminum heat treated back to T-6 after welding. The structure holds around 2 pounds of material and we've heat tested it to 95C and 2700 PSI, but we rate it for 3000 PSI and it's true yield strength is around 5400 PSI .The problem I've run into is that I have no idea how to separate the final material from the CO2. What were you planning?
-Max

 

[Gray Wolf]

We deigned, simulated, machined, welded, and heat treated a structure from scratch, it's made of 6061 Aluminum heat treated back to T-6 after welding. The structure holds around 2 pounds of material and we've heat tested it to 95C and 2700 PSI, but we rate it for 3000 PSI and it's true yield strength is around 5400 PSI .The problem I've run into is that I have no idea how to separate the final material from the CO2. What were you planning?
-Max

Out of old habit, I typically design pressure vessels to 3X their intended operating pressure. For operation at 5ksi, I am designing for 15ksi.

Are you speaking of separating the plant material from the CO2, or constituets in the CO2 extract?

For the former, I plan to vent the liquid out the bottom of the soak chamber, into an expansion chamber, from which I could bleed off the CO2 as a gas and leave the oil behind.

 

[Hydro-Soil]

Are you speaking of separating the plant material from the CO2, or constituets in the CO2 extract?

From what I can tell... he's asking about separating the wanted extract from the unwanted contams in it...

Is the CO2 pull clean enough that no further processing is needed? If so, what temps and pressures and times are used to achieve this. (Generally speaking... like default values for any vessel)

This is just awesome... definitely need to get a community unit up here.

Stay Safe!

 

[c-ray]

hi Gray Wolf, for some ideas about multiple chambers you should have a look at this page: http://probase-technologies.blogspot.com / which is based on the patents of a guy named Peter Wilde.. I'm not suggesting using 134 but thinking perhaps the design might be of value..

 

[G.O. Joe]

I was thinking of something to make collecting the finished product easier, if close tolerances aren't a problem. How about a separate top, on a cylinder with capped hole at the bottom (or on a separate base); the CO2 is bled off at the top, the top is removed, a piston goes in, the top is replaced, the cylinder is heated, and compressed gas forces the piston down.

Or, maybe, as the pressure and temperature goes down, all the product magically precipitates on a flat bottom, long before the CO2 is gone, instead of on the side of the cylinder. Maybe with a certain bleed rate or combination of heating the sides and cooling the bottom. Maybe not.

A few predicted and found solubilities (as mol/mol fraction of CO2) at different temperatures, from this abstract. Don't get too excited, these should read 10-4, not 104 (no sub and sup BBCode to say that right).

At 315 K:


At 326 K:


At 334 K:


If I figured this right, the maximum solubility they have for THC is about 1 gram per 600-700 grams of CO2.

 

[maxrosen666]

Grey Wolf, you got it right. Im trying to build a separator that goes in after the SFE chamber. But what I've tried so far has shown little promise. I have a pressure regulator on the bottom of the chamber and I vent at a very low pressure allowing the supercritical CO2 to phase change to a gas at the regulator. Once the phase change has occurred the extract is no longer in solution and we have to use the mechanical factor of CO2 gas pushing through a tube to get the extract out to the separator. But when the extract falls out of solution we can expect it to be in very small groupings, making it very hard to collect. I worry that even though I'm regulating at very low pressure and therefore very low velocity (through the tube), I may incur some loss if i just shoot it into a beaker. Because it's essentially blowing minuscule bits of THC dust which may just escape into the surrounding environment.

So to clarify your separator; you want to create a secondary low pressure chamber that you vent gaseous CO2 into, then let the extract settle to the bottom do to gravity and then slowly vent the CO2 out of the secondary chamber, and then do this over and over until you have a pile of material at the bottom? I like this idea I think this might be what Im looking for. Also what are your feelings on utilizing water in the separator as opposed to just gravity, I thought it might make sense to fill the separator with water (RODI for cleanliness sake) and have the CO2 bubble through. Because it is polar the THC wont dissolve but it might help as far as a medium that the extract can sit in, as opposed to just an empty chamber where you might accidentally blow your extract out during separator venting. (I feel I might not be explaining this water idea perfectly, I can send you more info to clarify this part if you like.)

The other problem that Im seeing with my soak chamber is that we technically depressurize the chamber at the exact rate of CO2 leaving the chamber. Because supercritical CO2 is technically a gas, it behaves as such in terms of holding pressure. so as we vent the chamber the pressure drop is directly correlated to how much CO2 we lose. This means that our pressure drops very quickly and we risk dropping out of supercritical phase and into gaseous phase which in-turn means that we lose the solubility of supercritical CO2 and possibly leave some extract behind. This is as opposed to when CO2 is in a liquid state, it can hold pressure for a very long period of degassing because the liquid CO2 boils to gaseous form to fill the space, maintaining an equal pressure until almost empty. What I'm thinking of doing to counteract this problem is switching to a "semi flow chamber" Where we initially fill with liquid CO2 then go into supercritical phase via temp increase. Then soak, then discharge right up until the point where the CO2 would fall out of supercritical. Then refill the chamber from the tank, adjust the temp and let it soak again and again. So we constantly maintain supercritical state and guarantee all removal of extract based on the quantity of times we refill the chamber.

Any help or ideas would be much appreciated and thanks for showing interest so quickly everybody. I can post a few pics if you'd like to see the chamber?
-Max

 

[Gray Wolf]

hi Gray Wolf, for some ideas about multiple chambers you should have a look at this page: http://probase-technologies.blogspot.com / which is based on the patents of a guy named Peter Wilde.. I'm not suggesting using 134 but thinking perhaps the design might be of value..

Thanks for the link! Looks like the same basic system as the butane extraction concept FOAF conceived, but I want to know more about their recovery technology.

 

[Gray Wolf]

Grey Wolf, you got it right. Im trying to build a separator that goes in after the SFE chamber. But what I've tried so far has shown little promise. I have a pressure regulator on the bottom of the chamber and I vent at a very low pressure allowing the supercritical CO2 to phase change to a gas at the regulator. Once the phase change has occurred the extract is no longer in solution and we have to use the mechanical factor of CO2 gas pushing through a tube to get the extract out to the separator. But when the extract falls out of solution we can expect it to be in very small groupings, making it very hard to collect. I worry that even though I'm regulating at very low pressure and therefore very low velocity (through the tube), I may incur some loss if i just shoot it into a beaker. Because it's essentially blowing minuscule bits of THC dust which may just escape into the surrounding environment.

So to clarify your separator; you want to create a secondary low pressure chamber that you vent gaseous CO2 into, then let the extract settle to the bottom do to gravity and then slowly vent the CO2 out of the secondary chamber, and then do this over and over until you have a pile of material at the bottom? I like this idea I think this might be what Im looking for. Also what are your feelings on utilizing water in the separator as opposed to just gravity, I thought it might make sense to fill the separator with water (RODI for cleanliness sake) and have the CO2 bubble through. Because it is polar the THC wont dissolve but it might help as far as a medium that the extract can sit in, as opposed to just an empty chamber where you might accidentally blow your extract out during separator venting. (I feel I might not be explaining this water idea perfectly, I can send you more info to clarify this part if you like.)

The other problem that Im seeing with my soak chamber is that we technically depressurize the chamber at the exact rate of CO2 leaving the chamber. Because supercritical CO2 is technically a gas, it behaves as such in terms of holding pressure. so as we vent the chamber the pressure drop is directly correlated to how much CO2 we lose. This means that our pressure drops very quickly and we risk dropping out of supercritical phase and into gaseous phase which in-turn means that we lose the solubility of supercritical CO2 and possibly leave some extract behind. This is as opposed to when CO2 is in a liquid state, it can hold pressure for a very long period of degassing because the liquid CO2 boils to gaseous form to fill the space, maintaining an equal pressure until almost empty. What I'm thinking of doing to counteract this problem is switching to a "semi flow chamber" Where we initially fill with liquid CO2 then go into supercritical phase via temp increase. Then soak, then discharge right up until the point where the CO2 would fall out of supercritical. Then refill the chamber from the tank, adjust the temp and let it soak again and again. So we constantly maintain supercritical state and guarantee all removal of extract based on the quantity of times we refill the chamber.

Any help or ideas would be much appreciated and thanks for showing interest so quickly everybody. I can post a few pics if you'd like to see the chamber?
-Max

Yes, or do it slowly enough to have a constant vent and deposit of oil.

If the collection chamber is pre pressurized and a valve between the process chamber and collection chamber is opened and the CO2 allowed to flow into it by gravity, when the top vent valve in the collection chamber is opened, it should allow only gas to escape, leaving the oil behind.

If you open the bottom valve in the separator, the oil will be forced out through the valve, under pressure. The separator would need to be easily opened and cleaned inside, to remove residual oil between batches.

I hadn't considered water and would be interested in seeing more detail.

I would love to see a picture of your vessel.

Where I currently am, is actually using three chambers, to better control the pressure and temperature that the material is exposed to.

The first chamber contains only liquid CO2 or dry ice, and is heated to build pressure higher than the desired operating pressure, so that when it is equalized with the second chamber, containing the plant material, the balanced pressure between the two is at the desired operating pressure.

The third chamber is the separation and collection chamber we've been discussing.

 

[c-ray]

I'll dig up the patents for you, good reads none the less..

 

[JYNdustriez]

In my opinion and burgeoning experience it is not necessary to transfer the solution as a supercritical gas. It would certainly be faster as far as collection of the oil goes because you have the increased solubility ergo more moles solutes per moles solvent.

At any rate it seems that just by making the batch go supercritical, a good portion of the covet-eds are removed from the plant material . When the chamber is depressurized and the CO2 recondenses at least the oils were in solution outside of the plant material itself, leaving them behind in the container for the liquid co2 to carry out as opposed to still being locked in the plant parts.

When I used to attempt spraying the final filtered liquid solution into room temperature atmosphere and a glass jar I noticed, while s***ting my pants because of the sputtering, that the CO2 does not purge completely out of the bright yellow oil/wax immediately. It remains runny for a few moments. I imagine under enough pressure to keep co2 a liquid, the consistency of the semi dissolved oils is such that it mostly runs with the liquid co2 during transfer to another tank via siphon tube. Nonetheless, I have found my greatest success by performing supercritical (1300-1500psi) extractions in one tank outfitted with a siphon and allowing the co2 to recondense. Using ice/warm water I push the liquid to a collection tank. Then I distill the CO2 across the same high pressure line from the collection tank which has no siphon back into the extraction tank. Again, using opposing temps. I won't lie, this process is time consuming, but the parts can be sourced relatively cheap and it WORKS. So there is the tradeoff.

I use standard CO2 cylinders for these lower pressures. I'm looking at some medical gas cylinders currently that have higher operating pressures 2200-3000psi range from what I have seen.

 

[Gray Wolf]

In my opinion and burgeoning experience it is not necessary to transfer the solution as a supercritical gas. It would certainly be faster as far as collection of the oil goes because you have the increased solubility ergo more moles solutes per moles solvent.

At any rate it seems that just by making the batch go supercritical, a good portion of the covet-eds are removed from the plant material . When the chamber is depressurized and the CO2 recondenses at least the oils were in solution outside of the plant material itself, leaving them behind in the container for the liquid co2 to carry out as opposed to still being locked in the plant parts.

When I used to attempt spraying the final filtered liquid solution into room temperature atmosphere and a glass jar I noticed, while s***ting my pants because of the sputtering, that the CO2 does not purge completely out of the bright yellow oil/wax immediately. It remains runny for a few moments. I imagine under enough pressure to keep co2 a liquid, the consistency of the semi dissolved oils is such that it mostly runs with the liquid co2 during transfer to another tank via siphon tube. Nonetheless, I have found my greatest success by performing supercritical (1300-1500psi) extractions in one tank outfitted with a siphon and allowing the co2 to recondense. Using ice/warm water I push the liquid to a collection tank. Then I distill the CO2 across the same high pressure line from the collection tank which has no siphon back into the extraction tank. Again, using opposing temps. I won't lie, this process is time consuming, but the parts can be sourced relatively cheap and it WORKS. So there is the tradeoff.

I use standard CO2 cylinders for these lower pressures. I'm looking at some medical gas cylinders currently that have higher operating pressures 2200-3000psi range from what I have seen.

Cool bro! A picture is worth a thousand words. Do you have pictures of your process that you can share?

 

[JYNdustriez]

Thanks for responding. Ask and you shall receive. My very first set up. I will explain whatever you want.....

My 10# canister heating up for the very first time with a normal 3000psi CO2 regulator as my gauge. There are cheaper alternatives however as the regulator itself is not actually needed. Now I use a SS 316L 3wayT with 1/4 threads to provide a port for a lone high pressure gauge between the ball valve on the transfer hose and the brass inlet stem.



My gauge when it passed into supercritical range because I was excited about it being my first CO2 extraction!



Tiny amount of extract winterizing. Ending up with 0.9g from that first run, I was disappointed to say the least. But not beaten.



That same .9 after filtration

 

[JYNdustriez]

Winterizing portion from my first recycling run, this ended up as ~4g. As you can see about twice the ethanol, and still much darker than the first one.



My copper and brass siphon tube with 1/4 npt end and stainless steel mesh screen clamped to the bottom.




My 20 and 10# cylinders with the ten pound being heated for extraction. However I have found that the cylinders being of equal size makes the transfer of liquid faster, as well as the advantage of the full use of your co2 fill. I would prefer 50# cylinders, but the price increases quickly for large aluminum cylinders. I played with the idea of steel cylinders, but they are certainly not stainless steel and would likely release more iron oxide into our extracts than the aluminum cylinders will aluminum oxide in the event of a dirty co2 fill that had moisture. So I have stuck with the aluminum so far.



This is a 5A 120V thermostat with a 250w heating pad wired to it. 250w/120v=2.08A so we should be good as far as safety. I found it to be sufficient in providing enough heat to reach the pressures I have previously mentioned on 10 and 20# cylinders. I had to always ensure that the thermometer was snug against the heating pad otherwise the thermostat will read a low temp and overheat the cylinder trying to reach, impossibly, whatever it was set to.



I used 5 gallon buckets to provide the opposing temps for the co2 transfer. One with ice water, and the other with an aquarium heater.

So what ?'s of me have you?

 

[JYNdustriez]

Oh and this is my favorite pic so far of my extract. This is mayyyyybe 2g.



In case anyone was wondering, the largest difference between co2 extracts and hydrocarbon extracts IMO, its the TASTE! The sweet, sweet taste.

 

[JYNdustriez]

Most nitrogen tanks also have an operating pressure of 2200psi and above. I'm interested in the 3000 psi tanks in particular because of the solubility charts provided by the perrotin papers. There seems to be a significant jump of mole fraction solubility close to 200 bar in most temperature ranges.

Significant