You can do a plate heat exchanger or a tube in Shell heat exchanger and inject into your heat exchange liquid flowing to the heat exchanger your CO2 directly to it for maximum efficiency just make sure you account for the expansion of the gas and not blow up your lines.
Edit: it would be safer too have a closed steel tank with a blow off valve that’s part of your system in which you will inject either CO2 or LN2 before it gets pumped and circulated through your heat exchangers
It may be even easier to find out which type of recovery pump will pull a hard enough vac to self refrigerate your solvent tank. It seems like @Zack_illuminated uses some sort of compressor pump if I remember correctly
I think the venting in the slurrry makes sense to avoid freezing of the coils end for that a humidity isseu of atmosphere and beeing submerged should not happen
The dewar I meant is the non pressure dewar full open insulated cap
As for working with liquid nitrogen things get more complex reason that even your butane can freeze up in the coils so any butane that stays stalled in the coil can freeze and plug it shut
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Self refrigeration of the tank only go s so far and must be a strong pump to fight the vapors and keep lowering the vacuum and thus the boiling point would imagine a load of vapors needs to be boiled of befor you get anywhere near -40C on the whole solvent tank
At a massive speed
Theoretical it should be possible but not easy
Hmm if one would have massive pumps and electricity for free it would be a cool thing thou
Have R507 in a coiled tank and recover this
And run butane treu the coils 
Seems like a good resolution to me as well. Would I be injecting liquid CO2 at pretty much full bore, and using a valve at the end of the coil to throttle venting for temp control?
I’d be more concerned about that plastic bucket…
hmmmm your average ball valve is not made for these temps and check if it s solvent proof since it will be bathing in there need to be checked
I would use a high bin not just for the boiling but also for the whirl this off gassing will create
May be where I got 75PSI from. Very smart man.
How much searching have you done on the subject?
@Zack_illuminated is another smart cookie, he looks at that same graph and ALSO sees 75PSI as the min
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It sounds like the move may then be to put a prv set to ~125psi on the end of the coil, submerged in denatured, and throttle cooling with a needle valve on the coil’s inlet
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I can bring 30 gallons of tincture to winterzation temps in under a hour using about 30lbs of Co2.
A key is to have steady flow, a diaphragm pump will not preform very well because the flow is pulsing slower as the tincture cools.
Ideally you want to use the gas you create to offset the cost. If you have a Co2 extractor you can purge, fill and run your pumps off of the gas. If you have a grow you can store the gas in tanks like compressed air for Co2 enrichment.
If you can get your Co2 for less than 25¢ a pound then it’s probably cheaper to cool with liquid Co2 vs the electric cost to cool with refrigeration.
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Exergy coils?
Yes, the high pressure model. One isn’t enough surface area to evaporate the Co2 so stage them in pairs and that will allow for better efficiency.
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what are you using for a pump with these? Honestly I thought there’s enough pressure in a cryo-tank that a pump wouldn’t be necessary
Lco2 is complicated to understand until you use it, and find where it’s most efficient, needle valve is a must as liquid expansion is what collapses things prv 100psi.
Look at it this way, you are not trying to use the liquid as a liquid, you are trying to make dry ice with it.
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Make enough dry ice to cool the medium, but not enough to clog your system? Interesting, I’d love to see it done in person
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That is the idea, if you get it right, it doesn’t really clog…
Come to Montana, ill show you
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CO2 is high pressure at 800+psi. As suggested above, make sure the system is robust enough to handle it.
Hey sorry for the delay on this, @Cryo13 hit the nail on the head. The goal is to keep the liquid under high pressure until it’s in the jacket. This ensures it stays liquid while running through your lines.
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Can you define “high pressure” for this use case? Ie target and prv settings?
I’d use LN2. There’s a lot less to go wrong. I’ve used it to directly chill solution while it’s also used to move solution through piping with a venturi. It doesn’t change the solution PH. It pumps and chills like a charm. It doesn’t create dry ice. It doesn’t displace oxygen like co2. It’s main downfall compared to co2 is the $/btu.
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