Supercritical CO2 Extractions (Dated)

28 April 2013
So I have some cautious yet exciting news. This week I will have my parts for a simple extractor. It will be supercritical, and the plant material will be immersed in the CO2 throughout the entire pressurization. That means that there will be no selectivity via pressure or temp but a more thorough extraction for those of us not looking to throw away usable oils over a little extra wax and other solubles. In a commercial extraction scenario it may make more sense to give up a little oil vs clogging filters after ethanol winterizing. In the home however, it does not make more sense because cleaning or replacing filters ever so often is inexpensive and hassle free. When I build it I will explain every thing about the extractor. I am also sourcing parts to make solvent reclaiming systems.

01 May 2013
All the parts are here and I plan on a test run tomorrow. Fingers X'd.

05 May 2013
There was a hiccup in getting the CO2 tank filled, I ended up just purchasing my own tank with a siphon tube....... Anyways this week it will happen, I promise not to flake on this! Keep reading on and in a couple of days you WILL see the end product of an at home CO2 extraction at supercritical pressures and temps.

06 May 2013
5pm
Hehehehehehehehehehehehehehehehe

These are a few pictures from my first primitive extraction. Don't be alarmed by ugliness.





Getting warmer....

630pm

Well isn't that just SUPER!


I have passed the phase line pressure/temp for CO2 to go super critical. I will let it rise to about 1300 psi before I maintain the temp that gives me that. This is just to ensure that all of the CO2 goes into this phase.

Now, here is my safety spiel. The cylinders I use have an operating pressure of 1800 psi, and a burst pressure minimum rating of 4500 psi. The valves are outfitted with 3000 psi burst disks to ensure a controlled depressurization long before the burst pressure. As well, the regulator will depressurize if 3000 psi is reached. I am using a thermostat and scientific heating pad to control the temperature. My method includes  filling the canister to 50% volume as opposed to the 68% volume they are rated for. I am giving my self more head room for temperature and pressure fluctuations.

I will be continuously updating this post with details throughout the night and the next couple of days as I winterize and purge whatever I produce from these 57 grams of flowers.....

Did I mention that I'm going to have a retail model ready by the end of this week? (tilts head slowly to the left and smiles)

Full write-ups to follow.

845pm

So I decided to release the tiny bit of supercritical gas in my regulator because well, I'm a weirdo. I let it sprinkle and condense on the back of my hand my god I have never smelled such a sweet aroma....... I'm going to let the extracts dissolve a little while longer. According to the guys at Skunkpharm four hours should be sufficient using supercritical CO2. Then, I'll cool off the cylinder and allow the CO2 to condense so I can release it slowly as a liquid into a pre-chilled glass jar. As always I strive for simplicity and the fewest number of steps possible to achieve excellent results. TBC........

07 May 2013

So you would probably like to see pictures of my early fruits.....

Update on photo below:
Venting oils dissolved in CO2 into open air or even a vented jar is impractical and likely to cause losses eventually. I no longer collect oils this way. They are reclaimed with everclear after the CO2 is vented as a gas from the collection tank leaving the residue behind.













<Beginning to winterize.


Thoughts before bed:

One more "rinse" of the cylinder with liquid CO2 tomorrow, because I am certain there is more oil stuck to the walls. Reheating/pressurizing should not be necessary.

The smells during this extraction were sweet.

Tweaking to the set-up as expected is necessary!

Negative on the glass jar, only a solvent reclaiming system in the case of CO2 is reliable because it keeps the solvent in its liquid phase, no dry ice or oils clogging gas regulators and valves. There is a lot of spurting that goes on if this is not addressed it seems.

The system available at the end of this week will feature two cylinders: a 20# liquid CO2 storage and transfer tank, a 20# extraction tank. Dual safeties in the event of an over pressurization are in place, as well as thermostat controlled heating. I will provide a safe CO2 extraction system for a price that is competitive with the leading hydrocarbon extraction companies.  <$2000 for a sixteen ounce system.

08 May 2013

I conducted another rinse with liquid CO2 and evaporated it from the tank leaving the oils behind to be picked up by ethanol for winterization. I was much more able to reclaim my oils in this manner as opposed to attempting to vent the CO2 into a jar. Silly me for every trying it that way in the first place.

Thank you for your patience and I look forward to the future! - JY

09 May 2013

I can not help but feel that the oil looks more appealing with each successive run.


2 comments:

  1. But PSI is not BAR :(
    http://www.natex.at/RDUnitsusw.html
    i think by only 70bar you need min 10-20h extrection-time... take more time to got better results ... and 10micron filter is BIG ;(

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  2. Thank you for commenting :). Where did I say PSI is equal to BAR? Now I extract above 200 bar every time and usually around 215 bar. Many times I have left the material pressurized overnight and it did not yield any better than a four hour extraction time. I think it was because I had no way to flow the CO2 and/or agitate the contents. My plant material kind of just sat in the bottom. Now I use smaller cylinders so a larger percentage of supercritical fluid in the canister has contact with the plant.

    Honestly, this page is far from my technique now. I am so busy with school and building things that I am just doing my best to keep up. However, I am updating soon with all of my changes. - JY

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