Hi All,
What are yall’s thoughts on this
Heat exchanger is a brazed plate. EtOH vessel would be jacketed. Pump would be an air-operated diaphragm.
Any input is helpful.
-Phil
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diaphragms begin to suffer down into the -70c range and may not take continuous duty. be wary.
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I used to do that with a recirculating chiller. Worked great.
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how are you avoiding frozen EtOH in the heat exchanger?
Solenoid valve on LN2 supply that is either relay fed or 4-20mA based on ethanol outlet temp
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which works unless the ethanol stops cooling the sensor because it froze and isn’t flowing?!?
does there also need to be a flow sensor?
I ask because I want to go here too…
edit: I think I like option 2. 4-20ma
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Fundamentals of Controls professor would probably say that several control stream could be created; level, temperature, flow.
You could use a “feed forward” loop and also utilize the incoming temp as a control.
Key to not freezing would be accurate control and not too low a set point.
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nobody ever taught me control 
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I don’t see anything that immediately makes me go “nope, won’t work” but I also get the feeling that the devil is likely in the details on this one and will probably take way longer than is reasonable to work just right. Not that it’s not worth that time/effort of course.
tl;dr I like it.
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Why not recycle that gaseous L2 have it agitate your ethanol…
That’s what I did to get to -190…
Let’s get these efficient ideas going
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My attempts at that approach have “agitated” the ethanol violently out of the container. 
Fun to watch, but not particularly safe or useful.
I know @TheGratefulPhil’s approach will work, because this can be purchased solved.
Capturing more of the chilling power by using the cold gas is also the right approach.
Holding some back to move the solvent around (just setting the prv correctly) is also a useful trick.
Can I come see how you’re getting the job done?
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I’m into the idea of using the subcooled gas to chill additional systems, or perhaps even the ethanol; but here’s a parts list for the first design:
Same. LOL.
My first iteration was the following. NOTE: I am a trained retard so don’t try this unless you know the risk. SAFTEY SAFTEY SAFTEY.
BrotanicalMatt’s death wish tek. (first iteration)
1 Stainless steel drum. (must be stainless because i froze a drum to the floor.)
30 pounds of dry ice.
20 liters of L2.
Bubble bag dudes - 220 micron bags.
Flower.
1). Line bottom of drum with crushed dry ice.
2).Pour about 1-1.5 gallons of Ethanol
3). Put BBD’s micron bags with about 5 pounds of FROZEN flower.
4). Thow dry ice carelessly in-between bags.
5). Ethanol at ratio of 1gallon to 1 pound.
6). Pour L2 and ethanol in at same time. LOL.
7). Watch the world burn.
8). Personal Preference - take out bags of flower before -120c. This is where i have seen fats and lipids leech through.
9). Let warm.
The end product should have a beatiful golden color.
Reasons on why i chose do this way AT FIRST.
Ethanol freezing temp is -114c. I asked myself, how do i break physics… Turns out it hit me that just like you would on a cold day - keep your faucet running so water doesn’t freeze the pipes.
The nitrogen is turning into a gas since it’s warm to that noble gas properties. The Co2 is subliminal from a solid to a gas. This creates a “boiling illusion” from all the gas pressure expanding. It super freezes the extraction and at the same time. I have micron bags that are filtering the product and allowing for agitation of the biomass itself. Essentially is utilizing not only the chemical itself for the extraction but the secondary properties that each individual compound has. Kililng 4 birds with a stone or something…
Efficiencies to the max. Since then i have found equipment that would make this process much more scaleable. However, i shelved it because my business and place in this industry is to help the farmers and extractors get more value for their products. I am not here to compete with people who are already in a croweded market.
This was just a small R&D project…
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I will show you my thoughts on how to make it work and eqiupment that we think would do the job.
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see through?
FFE with training wheels?!?
Edit: the all knowing one says Gasskrubber… guess I should keep digging 
https://www.christianberner.se/produkter/vatsketeknik/glasanlaggningar-och-komponenter/gasskrubber/
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Not worried about acidifying your ethanol??
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Ethanol is already acidic. The hydrogen of the hydroxyl group will react with a strong enough base.
In the system we came up with we wouldn’t use Co2. We really like the idea of inert gases being recycled. At scale if i cant measure my solvent/gas loss in the PPM’s. Im not interested.
@cyclopath - Just remember who did it first
What about recycling your nitrogen that’s been vaporized into the headspace of your cooling vessel. Reduce agitation by pressuring the headspace and inert simultaneously?
A cryogenic back pressure regulator can be your friend here, install on LN2/N2 outlet line of the HEX. I use BPR set @ 125psi. Making use of that cold gas discharge is always a good idea.
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