Hello Future 4200, this is my first post on this website.
I have ran a Waters CO2 extractor for a few years and have now switched to a xact xtract LM7 extractor. This new extractor is quite unique, very manual and almost no sensors. The max pressure we could get to on this instrument is about 1000psi, the extraction vessel is not jacketed or heat controlled and I have no flow gauge. I do have the ability to add ethanol into the system to help pull more of my yield out.
Questions
Has anyone ran this extractor and have general advice?
To pull terpenes running subcritical CO2 would a pressure of 400psi be optimal, also should I have to heat in the collection vessel turned off?
Has anyone had any luck pulling cannabinoids out with CO2 at pressures of 850-1000psi?
Using ethanol as a co-solvent are there any suggestions on how to increase extraction efficiency?
I am only 5 days in on this extractor so I have so much to learn, thank you for any help!
You may have better luck calling the Vendor Azoth a call. To my knowledge these are pretty new; and there is not a lot of data from these machines. I could be wrong but that may be your best bet.
Thank you for the reply, I have been trying to reach them by phone but that is a very difficult task. I will post up any response I can get from them though.
As for the age of this extractor to my knowledge this company acquired it in 2017-2018, so I am hoping there is someone out there with knowledge on it.
In order to keep your CO2 in the liquid state at that pressure, the temperature needs to be at least -9 degrees Celsius or lower. Any warmer and the CO2 is just gas. The other factor you need to consider is the density of the liquid CO2 and the optimal solvent density for extracting terpenes.
Both have low boiling points. Might be challenging to separate your terpenes from your ethanol if you don’t have the right rotovap or distillation setup. On the other hand, works great for your heavier fractions and plays right into winterization.
These are low pressures even for subcritical co2. Would be a long extraction time depending on your input weight and the yields are still not that great, however, the quality is legit.
I understand though that this is your limiting factor. At 850 - 1000psi, your optimal temp should be around 14 - 17 degrees C. This plays into the solvent density again, specifically targeting your heavier compounds like cannabinoids.
Start playing around with different pressures and temperatures ON THE COMPUTER OR ON PAPER. Although you are trying to find parameters that keep your CO2 in the liquid state, they also affect the density of said solvent. Terpenes have an optimal range of solvent density for extracting and so do cannabinoids.
Your going to need modification to make the LM7 extract effectively.
It’s a passive Co2 extraction system that can be cooled with Co2 from the dewar or a chiller.
The system needs heated surface area to function properly, currently you will just flood the system with liquid or drop the pressures below extraction ranges. There simply isn’t enough heat input to boil the liquid created by the condenser, without addressing that problem you will always run into issues.
I would suggest a full CXE injection conversion to make the lm7 even worth running.
It never worked correctly, it’s a long story of greed and embezzlement. I was voted out of the company “with cause” for telling the clients the truth about their equipment.
These weren’t the machines I designed or set out to build, they hoodwinked me into thinking that we were building my new design when in reality they were just buying old assets and designs and rebranding them as extraction systems. By the time the first machines started to be delivered they had already pocketed $3mil, thus far they have made $25mil.
Not one of the systems work as advertised, I am the only support left for the people unfortunate enough to buy a Azoth system.
I have to give my eternal thanks to everyone for posting so much helpful information!
Sorry for the late reply but I would like to attempt to address all the comments made.
I was able to set the extractor to these conditions, but the flow rate (only can tell by the sight glass) seems very slow. After 1 hour of running like this I was only able to get about 1g of extract.
Extraction based on solvent density is definitely what I am familiar with, but I do not have the ability to know the temperature of the extraction column so this makes it fairly difficult to control. Today I am experimenting with running the condenser at different temps. Currently I have the condenser set to 5C and the pressure is at 600psi, this should give me a density of 0.92 g/ml the main issue I am seeing is the flow is almost non-existent…
You are my guardian angel! Alright we have a little to unpack here -
1 - I have been seeing quite a bit flooding in the sight glass especially at the higher pressure and temperature that this crew is used to running (950psi, 20C). Would a heated jacket on the extraction vessel help remedy this situation?
2- A full CXE injection - we have the ability to vent the accumulator and add ethanol into the system. I have found best use is ethanol at 5% to CO2, I have been having issues recovering the ethanol I have added in. I have in the past done ethanol “pulses” basically add ethanol into the system at the “correct ratio”, give a longer resonance time in the extraction vessel, than use CO2 to clear out the ethanol from the vessel. The issue I am having here is the collecting of the ethanol from the system, when I have added in ethanol I will not really be able to recover the majority of it until I have vented the system down.
Wow, I mean what else can I say here… I was told when I started here that this instrument was called a unicorn, upon closer inspection it is just a donkey with a cone on it’s head.
Follow up questions -
For terpene collection is there any way to increase the flow rate?
For collecting terpenes do I need to install this low pressure collector?
Large capital investments are difficult to make currently so buying a new system is not an option currently, also we are utilizing BHO extraction as well but CO2 makes it’s own quality product that consumers like so we would love to be able to get this system working!
Thanks again to everyone for helping, I am eternally grateful!
I’m not surprised by the low yield though, liquid CO2 extraction is a LONG process. The reason is because liquid CO2 does not have effusion properties like gas or supercritical fluids. Yields and time efficiency are a hard reality.
Maybe I grazed over it, this is a passive system so you don’t have a pump with it. I wonder if you could mod it with one?
I was able to crank my pressure and temp to 700 psi and 10 C this allowed for some collection of what looked like and smelled like a fairly terpene heavy oil. I am trying to adjust the conditions to control for solvent density and I read that a density of 0.3 g/ml is good to target for terpene collection? I haven’t been able to get that low yet but I am working on it!
Definitely a passive system but I can control the heat in the collector (with a water heater, not very accurate) to adjust that amount of CO2 that gets converted to a gas which then allows for the CO2 to cycle in the system. The issue is it does heat the system a bit and I was unable to maintain a pressure of 400psi, which I was told by the manufacturer that 400 should be my target for terpene collection.
Thanks for the response it is very nice to bounce ideas off knowledgeable people, another update is it does look like the ethanol addition I attempted got a decent amount of material out my finished yield could be high teens, low 20s. I am still having a difficult time collecting ethanol especially at higher pressures but it is progress!
Maybe people extracting crude could add some ethanol to their butane to increase efficiency. They still would recover 90%+ of the butane solvent but I bet yield would go up
Maybe a first soak with butane only then a second soak with butane ethanol in whatever ratio it actually mixes
You can get the above heat exchanger with 1/2" tube ends which can be placed directly above the “collection vessel”. This will create a falling film evaporator that can boil the majority of the Co2 away before it can accumulate and flood the “collection vessel”.
The system can only passively circulate at pressures from 750psi to 950psi. Because the solvent flow is 100% gravity driven and the density of the liquid and gas phase of Co2 cross at near critical pressures the system has a steep drop off in flow at pressures that can extract cannabinoids. A real conundrum for a Co2 extraction system…
Your only option is to add a solvent that’s soluble in Co2 at the pressures that the system can circulate at. You are extracting with the solvent but in a suspension of liquid Co2 and then removing all of the solvent from the biomass by circulating liquid Co2 as a rinsing solvent.
As you have experienced your ethanol seems to “disappear” in the system. You are in fact sending the ethanol to the storage tank or blowing it out of the vent. So long as your “collection vessel” floods sending the contents of your “collection vessel” into your vapor stream you will never have consistancy from the system.
Adding a CXE injection kit to the system will eliminate the variable mixture of ethanol and Co2. With a metered injection while the system is circulating at 750psi you can maintain consistently in the ratio of ethanol to Co2.
With the exergy heat exchanger installed and a metered injection of ethanol you should be able to start to get some good pulls out of the old donkey.
Would the blue or red arrow pipe be replaced with this heat exchanger?
Thanks for this information it explains what I am currently seeing. Nice to know the expert!
I had a suspension on that but thank you for clearing it up! This heat exchanger for solving the flooding issue seems very important. Increasing the temperature of the collection vessel should help me somewhat then with the flooding issue? Would you also suggest that 750 psi pressure for collecting ethanol? I have seen on other systems that if the pressure and temp is too high the ethanol didn’t crash out. Thanks for the knowledge!
I will research more!
Do you get the terpenes to collect at that pressure as well? I was at 750psi/50F yesterday with mild success. I also have the issue of residual ethanol in the system that I believe is coming out with my terpene fraction.
The optimal solvent density is different between monoterpenes, sesquesterpenes, terpenoids, etc.
Liquid CO2 is very dense with respect to the ideal solvent density of the terpenes. The density range is roughly somewhere between 750 kg/m^3 and 1300 kg/m^3.
Because of this, you will need to filter/centrifuge out any fats/waxes/lipids, and cannabinoids from your light fraction, regardless of your set parameters. Terpenes extracted using “supercritical fluid” can go through these refinement processes too even though it is not necessary.
