I will just be hooking it up to the exchanger with a needle valve and letting it passively flow through the other end. So a plate exchange it would work much better for this the only downside being a much higher cost?
ADMIN EDIT: Please note this post was accidentally submitted in this thread instead of Turning my co2 extractor into a cryochiller?! Gas expert needed! :) - please disregard 
I would suggest something to function as a restriction point between the high pressure extraction vessel and the lower pressure separators. The expansion point can be a needle valve or a small nozzle to restrict the flow and allow for lower pressures to be maintained in the separators. The lower the pressure you run on the separators the lower the cooling temperature will be. You will still need a water chiller to run a closed loop cooling cycle in your system. The heat from compressing the separators to higher pressures has to be displaced somewhere for the refrigeration cycle to continue. Your chillers need to be able to hold a steady 5c under load for you to get the best performance from the co2 cooling.
Your separator’s jackets will function as your heat exchangers. Pump the extraction solvent through the separator jackets flowing top to bottom for best exchange. Running your separators at around 250psi should cool your solvent down to -15f, 140psi should cool down to -30f
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My extraction chambers are half 55 gallon insulated drums they will not be high pressure
ideally youll want both, use city water to get your etoh down as cold as you can before running through the ln2 heat exchanger.That way you need less ln2 to do the job.
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So I need two heat exchangers? I’m confused
you should be.
that response almost certainly belongs in another thread…
right around here if I’m not mistaken. 
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Your correct, I am not sure how it happened. Sorry about that
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If you are cooling with a large delta T then you will want to use water to cool the fluid down to at least 75f before cooling down to cryogenic temperatures with a second stage of cooling.
Large variable loads can me managed better with water because of it’s high specific heat. The problem with water is that is becomes problematic to run at low temperatures.
For best performance use a first stage water chiller through a heat exchanger to pre cool the solvent. The second stage will use the brazed plate heat exchanger using LCo2 to cool the solvent to cryogenic temperatures.
If you want to just cool the barrels of solvent simply with Co2 you can use dryice to cool the barrels directly.
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I’m using liq co2 to cool ethanol but I don’t want to put dry ice directly in it.
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What did you go with?
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Thanks for the math!
First off I’m the FNG. Why not use a lab freezer that you can customize to hold your ethanol in? The freezer walls could be drilled ( being careful not to drill a hole in the coils) and you could run a feed and return line. Like this you can pump your ethanol in and out as you need.
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If you have a chest freezer you could build a kreezer. Kinda what I’m doing. Built a ss tank to line the freezer it only goes to -20 then how ever much etho I want to Bri g down I cool w ln2 per batch
That’s what we are looking at doing. But for the volume we need to cool it may cost too much. You could have a lab freezer with 3 tanks. 2 being pre chillers and the 3rd the vessels with the ready extraction fluid and have hooked it up to a cryo chiller as well. If you are going to spend that much on the lab freezer you need to be running cycles as often as possible and just having the tank sit in there won’t do it fast enough.
I’ve read you don’t want to direct inject C02 into the ethanol but what about LN2? We’ve been looking at doing direct injection into the vessel of ETOH. Of all the methods I’m seeing that direct is the most effient use of LN2 but does it affect the extracted oil any. The vessel will be prechilled to about -10-20C in a commercial freezer.
I like it. You could use a jacketed vessel and drill holes on the inside of the tank and install these. Plug the return on the jacket and run the LN2 through the jacket and out these collecting the gas on the top.
Has anybody come across a comprehensive and understandable computation that estimates how many kW of cooling is required to cool 1L of ethanol, by 1 degree C, using LN2?
Or any way of accurately estimating how much LN2 is required to cool “X” units of ethanol, by “y” units of temp?
Is there any way we can connect directly? I would like to have a discussion regarding a scaled up winterization system.
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It’s a pretty simple calculation. The thermodynamics terms you’re looking for are heat of evaporation for the LN2, and heat capacity for the ethanol.
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