Decided to just drop the tech. I’ll be working with hydrocarbons now, so, maybe someone here will find the information useful.
The keys to crystallization with CO2 involve proper stripping of waxes prior to dissolving the THCa into solution, and phase change of the CO2, or rapid depressurization.
I’m not going to list entirely specific parameters because from my investigation these machines don’t necessarily operate the same under the same parameters.
Utilizing SCCO2 (supercritical CO2) as opposed to scCO2, (subcritical CO2) one can extract the cannabinoid acids in a much more time efficient manner. Volatiles and waxes will mostly come off in the 200-300 bar @ 45C range. Depending on whether or not it was indoor or outdoor crop seems to be the predominant factor in wax content. After stripping the volatiles and waxes, moving the system to 300-350 bar @ 35C will allow you to get the cannabinoid acids into solution.
Last is the phase change. Once you have your acidic cannabinoids in solution, a rapid decrease in pressure is needed (100 bar decrease over 10 seconds) to cause a powdery precipitation of crystals. If contained in a crystallization vessel, the process can be repeated as many times as desired to force larger structures.
Any questions at all, feel free to ask. By no means did I perfect this technique, however, my results were repeatable.
Just like any other isolate in my opinion. I tried it with straight CO2 terps as well as SPD CO2 terps, the terps straight out of the machine are yellow/orange but tasted better imo, super stoney though. The SPD terps were a “cleaner” high but don’t taste as good.
Oh no, I didn’t mean that. Dabbing it by itself didn’t taste like anything at all really. I don’t care for pure isolates by themselves, CBD puts a weird sensation in my forehead by itself, THCa makes my eyes feel like there’s a ton of pressure on them.
It was separated and dry, then I added terps to it.
I did 5 runs this way, averaged 5% of the 18% total yield in crude weight in isolate. I would have to guess at the run times, probably 5 hours for 2.5 pounds.
The other 13% was waxes, terpenes, THC, and THCa that pushed through the system per it not being designed for the process I was applying it to.
Average crude yields were 12-18% and 10-12% on distillate with around 10% of crude weight in terpenes on average, depending on it being bud, trim, quality, etc.
Did you not get a ton of carbonate and water crashing out when you had your rapid pressure change?
I’ve created some weird results putting a pressure regulating needle on top of a separator column before. Sub 0C crash temperatures and 1200-1800 PSI to 500 psi pressure changes in a split second. I’ll be happy to share the pictures if you care to see. (Old experiment from several years ago).
Were the pump seals rated for ethane? I know the ones in the Waters were designed for things like toulene and heptane, I’m not sure how aggressive ethane is towards those kinds of polymers.
Also, I have some ideas for process optimization and vessel design. If anyone would like to discuss them, or team up to design a system meant for this process, feel free to reach out.
I’m thinking your issue was being sub critical. The change from 325 bar to 225 bar at the same temperature keeps the solution in the supercritical range, but, reduces the solubility enough to crash out the THCa.
Based off the pressure and temperatures I would agree the phase was quasi liquid/gas. I The drop out temperature was definitely below 0C. My thermal probe was registering 45-50F and that was down stream. Not convinced the white stuff is THCA. Thinking it may likely be carbonate created. Back separator had a cyclonic separation of oil. Main separator was completely cake with the hardened material.
