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Collection Vessel Problems - Leaking CO2

edited November 2017 in CO2 Extraction

We are consistently having problems with collecting our product during and after our CO2 extraction process (using Hi Flo 5L 2K).

We do two "pulls" (open Separator collection vessel bottom valve) while extraction is going on (1 pull 2 hours into process & another at hour 3) and then a final pull at the end of extraction (after 4 hours). Inevitably after a few grams (5 to 10) of product oozes out through the collection vessel valve, we get CO2 vapour or gas leaking through and have to shut the valve off.

We then depressurize the Separators and remove the collection vessel. There is usually 30 to 40grams of extract remaining in the vessel.

Often the extraction product is contaminated (frozen with CO2) and also has lost that beautiful orange, yellow colour it has during our pulls. The collection vessel is extremely hot and a lot of our product colour is going dark brown to black.

My question is why does the CO2 vapour leak through the valve when there is still so much product in the vessel still there. A lot of videos I see out there shows huge amounts of product coming out of the collection vessel valve and I never see CO2 leaking out in the process.

Extractor Pressure 1800psi, Extractor Boiler 51 degrees Celsius, Separator Boiler 57 degrees Celsius, Pumping @ 30psi

Many thanks in advance


  • It sounds to me that you have a separation of compounds in your vessel. When you take your collections during different times in your run, you are collecting the first fraction, second fraction, and tails, essentially. Each compound becomes soluble after the other compounds have been collected. If you take a test sample from each of your pulls, I believe it's safe to say, you would find a different ratio of cannabinoids in each.

    You have to give it enough time to settle to the bottom. What I have found easiest on the final collection is to start depressurizing the system and when I am down to about 100 psi I open the collection valve. this has given the extract enough time to settle in the collection vessel while still having enough pressure to push the extract out. When I depressurize and open the separator 1 collection vessel, all i am left with is the shatter on the sides to be scraped off. Make sure you take your time depressurizing. If you depressurize too fast you end up with the dry ice in your extract as you explain.

    Hope this helps

  • Dry ice indicates that you are venting too fast, the puddle of liquid co2 in the bottom of sep1 turns to dry ice because of the rapid depressurization. I never remove the bottom of my fx2 separator.

  • Thank you Frog Mountain and Flash Thunder - very helpful.
    Do you take any collections (what I call"pulls") at all during extraction or do you just wait till the end.
    What about extraction times - we do four hours.
    We are now extremely careful with depressurizing - thanks for confirming that
  • We typically wait until the end. I think 3-4 hours is appropriate for a 5L, depending on plant quality.

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