Damn, I can’t believe I fucked that up!
Can’t argue w a nomagraph.
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So actually, hate to say it, but the nomagraph doesn’t tell the whole story.
Relative volatility decreases (i.e. boiling point difference between two components decreases) as pressure increases.
The reason the nomagraph tool doesn’t work is because it calculates the BP for a pure component and not relative BPs in mixtures.
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https://www.chem.purdue.edu/gchelp/liquids/boil.html
“A liquid boils at a temperature at which its vapor pressure is equal to the pressure of the gas above it. The lower the pressure of a gas above a liquid, the lower the temperature at which the liquid will boil.”
Youre correct about the volatility decreasing, you’re wrong about how that effects the boiling point.
" Pressure : when the external pressure is:
- less than one atmosphere, the boiling point of the liquid is lower than its normal boiling point.
- equal to one atmosphere, the boiling point of a liquid is called the normal boiling point.
- greater than one atmosphere, the boiling point of the liquid is greater than its normal boiling point."
Increased pressure does push the boiling points further apart I’ll use toluene and the nomograph to show you
Yes there’s other things that come into play when you’re evaporating a solution, there principles do not change though.
Read what I posted and get back to me. We’re talking about distillation of mixtures, not pure component boiling point temperatures.
Edit:
Here’s an article I wrote for SciPhy a few years ago that specifically addresses this issue. Vacuum Theory Fundamentals - SciPhy Systems
Here’s some actual data from a research paper you can find here about MIXTURES and not PURE COMPONENTS. https://www.jstage.jst.go.jp/article/jvsj1958/10/9/10_9_328/_pdf/-char/en
You can clearly see that with a reduction in pressure the relative volatility INCREASES meaning the two are more easily separable by distillation.
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I did read it and my response is still the same
I’ve shown it with math
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You haven’t shown it with math—you used the Antoine equation by means of a nomagraph.
Any chemical engineer (myself included) will tell you that application of the Antoine equation is limited for real world applications, especially as it pertains to the Distillation of binary, ternary and multi component mixtures.
The Japanese paper I linked makes this very clear.
You are over simplifying the problem by relying completely on nomagraphs.
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Actually I’m relying on my actual experience and engineers who are 10x smarter then me
Call me a BSer or whatever, my falling film that seperates methanol and water runs under pressure to increase the BP of the water way above that of methanol allowing just the methanol to vaporize
What do I know though
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I’m not arguing that you have a falling film under pressure to separate water and methanol.
I’m telling you that vacuum pressure increases the relative volatility between two components in a mixture in most cases.
This means they’re more easily separable.
This has to do with more than boiling points and a lot to do with distillation column design, chemicals included in the mixture and reflux rates, condenser temps, feed rates, etc.
Nomagraphs literally just give a visual of the Antoine equation and nothing else.
Relative volatility accounts for all the things I mentioned.
But what do I know? You seem to think that you’re the only one that’s ever correct.
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So you’re saying more vacuum will help Miles seperate cbd v and cbd?
I dont think so, it’s going to bring there boiling points closer together making it HARDER to seperate
I’ve yet to see any instances where vacuum distillation allows better seperation when BP are close
I’m saying that I have personal experience (and I have provided hard data above) that confirms that as a fact.
I have attained better separation of D8 / D9 at lower vacuum—I couldn’t completely separate them but the HPLC data we generated while running demonstrated definitively that at lower vacuum you achieve better separation of cannabinoids.
Next time you’re in OK, come by the lab and I’ll show it to you in person.
Here’s another example for methanol water that demonstrates that as pressure decreases, the partial pressure difference between methanol and water (relative volatility) increases https://www.prefeed.com/common/pdf/1205E.pdf
I’ve provided three hard examples with data at this point to verify what I’m saying. I will provide more as I find them.
Here’s a good conversation on stack exchange that explains this phenomenon. boiling point - Why does decreasing the pressure of the system increase the relative volatility of a binary solution? - Chemistry Stack Exchange
Again. This is not as simple as the “difference in boiling points is less at lower pressure” that only captures a portion of what is important.
You should be looking at the distillation mathematics—especially the VLE data and you can begin to model the actual distillation phenomenon using a graphical method like McCabe-Thiele instead of using Sigma’s Antoine Equation generated nomograph.
You are oversimplifying this phenomenon.
Edit 3: vacuum relative volatility - Google Search
Here’s a good sound bite that explains how vacuum improves relative volatility.
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Id give AG Chill a look for all chilling needs, amazing systems at a great price. Top Notch service, and made in the USA.
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I feel you, but again you’re talking about buying an external component that isn’t really necessary when you go with Illuminated. If processing were a direction that we intended to go in I promise you I would be having The Boss buy one of their skids. Again, nothing against the people/equipment you recommended
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I’d look elsewhere.
We’ve got a couple of them. build quality was terrible. they work. but only because we’ve spent time fixing them. still need more tweaks.
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How long have you had them? What tweaks are you seeing that need to be made?
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I’ve had two of them for 5 months.
More or less I would NOT recommend them at this point.
I could write a book on the issues I’ve had and am overall let down by the build quality and experience I have had with them.
To make it quick let’s just say both chillers have had at least 5 different fittings that leaked from day one.
They used wrong insulation, but since it leaked everywhere I had to pull it all off anyways to track down the leaks. Lots of NPT fittings which is a major NO NO on the transfer oil AG Chill themselves speced out for this build.
I’ve had custom parts fabricated and welded to fix the chiller in a faster timeline than ag chill could pull off.
We lost refrigerant on a chiller last week because they used slip on flared fitting instead of just flaring the line itself. The flared slip fitting broke right at the blob of solder. Simple 5 minute fix (we just cut the line and reflared the actual line and didnt use a slip on flared fitting.) except for the lost refrigerant it was a quick easy fix that shouldn’t have failed if they have better build standards.
I will say they have been on the phone with me daily to make it right but that’s no where near enough to make it right.
Having weeks of down time in the first couple months of running is absolutely unacceptable in my book.
EDIT: After some time getting these chillers dialed we have now been running 12-14 hours 5 days a week and the chillers haven’t stopped chilling. One chiller lost 1/2 a lb of refrigerant from a service port which has been switched out and repaired and recharged within a day and I have to say I would recommend these chillers to anyone that wants a solid machine that will perform reliably.
These were the prototype models and they have since built a handful of the same models and they have made the changes needed to keep them reliable and leak free. Joel and his team even came out to the lab on their dime after a few months of running and sharing run data and made some more improvements to the chillers to get them even more dialed.
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Youre the chiller king afaik
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Far from it, But I know enough to sound cool. 
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