Equalizing a column or getting everything in the boiler upto temp.

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Equalizing a column or getting everything in the boiler upto temp.

Post by shadylane »

Common practice is to hold a column @ 100% reflux for awhile before taking off any alcohol.
Here's something I've wondered about.
How much of the advantage of doing it that way, is due to "stacking the column"
And/or how much is from entire boiler charge getting up to temp?
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by howie »

i hold a rum spirit run in full reflux for about an hour, then the reflux is turned off and the run is done in potstill mode. apparently this releases more flavour.
with an neutral spirit run, i hold it in full steady reflux for about an hour.
after about 40-50 minutes, there is a slight temp temp change in the column, just before the RC. the temp drops about 2C, indicating (to me)that that column is in EQ/stacked.
(yes, temp gauges are useful sometimes)
apparently there is a slight vapour pressure when the column is stacked.
then the water and power is adjusted very very slowly to push the fores and heads through, which are very concentrated.
i have honed this method (only on a simple 2" column) and personally, the quality (and quantity) of the hearts is incomparable to my early attempts.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Yummyrum »

Have similar thoughts on this Shady but my line of thinking was if we think about a pot run , there is smearing because it take “that amount time “ to get “that fraction “ boiled out . So the stacking time is the “usual” amount of time the wash /low wines would need to boil to release them from the mix . The column just stacks them and holds back the next fraction .

Obviouusly , the column can’t hold all of the next fraction so alot while end up in the boiler . So because of the different mix in the boiler compared to a pot run , the time will be squewed from a pot run
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by kimbodious »

@howie, your observations are spot on! There are subtle signs that indicate the column is as stacked as it is ever going to be!
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by LWTCS »

Talk to me like I'm 3.
So sorry, but I don't really understand the question ?

As a general rule, we are simultainiously coming to temp, shifting alcohol into the column and allowing the lowest boiling constituents to occupy the highest available space prior to taking product.

What don't I understand about the question?
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by OtisT »

I think it would depend on the column. Size, height, packing material type, insulation, etc. I’ve just started paying attention to this myself and don’t have many records yet, but if memory serves me correctly it took my column around 20 minutes under 100% reflux before the stacked temps stabilized and stopped changing. I’ll be sure to take details notes on my next few neutral spirit runs. (May be a few months.).

Here is what I am using to determine this. It is a 4” stainless column packed with 43” of 1/2”- cinder rock (high mass). This is an older pic, and I have 6 thermometers stacked up the column now. I have a theory that using metal mesh packing will stabilize quicker because there is less mass. I’m saving up metal shavings now for a future test of this theory. I have a bucket of smaller grade cinder rocks too I hope to test, but that will be another thread when I find the time/energy to get to it. :wink:
4” column with thermometers
4” column with thermometers
I found it interesting that the difference in temp from one probe to the next is smaller the higher up the column you go. There is a big temp difference between the two bottom probes and the difference gets smaller the farther up I go. I really wish I had the height in my shed to add another 3’ to this. (That, and another 5500w ;-)

Otis

PS. It takes roughly 40 minutes to bring my 12 gallon spirit run kettle charge up to boiling temp.
PSS. Thanks Larry. I got my temp probes from Still Dragon.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

On my continuous stills it is really easy to feel the column coming up to temp. 4000 watts and a 3 gallon boiler goes fast.
One the boiler is boiling you can feel the steam going up by putting your hand on it. One second the outside is room temp, the next second it is 170!!!!! And it heads up the column

With pot reflux it takes so long to get up to temp. Then you want to run it awhile to boil ALLthe heads and foreshots out of the wash.
Like said above, on a pot reflux I will take off the heads about 5 minutes after it is up to temp. Then boil a while and pull some more off.
You can smell the heads and you will know when you have them all.
On a 5 gallon run I'm talking a cup or two total.
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Ben »

One of the side effects of my large tube dephlegmator on my two plate setup is I dont achieve full reflux if I am boiling at more than about 40% power. So I get about a drip a second. I also get a precursor few drops of an odorless flammable liquid well before the head starts coming up to temp, not sure what that is. I just let the fores go for 20-30 minutes, smells like acetone, gets thrown out. Once the solvent smells go away I turn down the defleg water and run.

I am curious how vapor can stack and separate in a column though. Once the solvents and alcohols are in a vapor state they take up a lot more volume than a column can hold... I don't know what the expansion rate of ethanol is at 0 psi, 1000x+ maybe? Water is about 1600x. I just don't think you can fit the liquid volume that foreshots occupy into a column/headspace of the still in the vapor state. I don't think you can fit even a fraction of the acetone, which is a tiny fraction of the wash into the column in a vapor state.

I buy Shadylane's theory on the boiler charge temp.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by OtisT »

Ben wrote: Mon Dec 06, 2021 10:31 am
I am curious how vapor can stack and separate in a column though. Once the solvents and alcohols are in a vapor state they take up a lot more volume than a column can hold... I don't know what the expansion rate of ethanol is at 0 psi, 1000x+ maybe? Water is about 1600x. I just don't think you can fit the liquid volume that foreshots occupy into a column/headspace of the still in the vapor state. I don't think you can fit even a fraction of the acetone, which is a tiny fraction of the wash into the column in a vapor state.
The column in equilibrium won’t be totally filled with the lightest vapor. Vapor in the column is a progression from low ABV vapor at the bottom (akin to a pot still) to higher ABV at the top as it is refined on the way up. You can see the temps on my column show this temp stack if you zoom in on that pic. 97C at the bottom. 96C a foot up. 80C another foot up, and 79C near the top.

You will never have refined vapor at the bottom. As you slowly take off the more refined vapor from the top, the column continues its work and separates/moves up more refined vapor to replace what you pulled off. If you take off product too fast, your column won’t have time to catch up and your takeoff ABV will suffer.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Ben wrote: Mon Dec 06, 2021 10:31 am
I am curious how vapor can stack and separate in a column though. Once the solvents and alcohols are in a vapor state they take up a lot more volume than a column can hold... I don't know what the expansion rate of ethanol is at 0 psi, 1000x+ maybe? Water is about 1600x. I just don't think you can fit the liquid volume that foreshots occupy into a column/headspace of the still in the vapor state. I don't think you can fit even a fraction of the acetone, which is a tiny fraction of the wash into the column in a vapor state.

I buy Shadylane's theory on the boiler charge temp.
There is vapor in the column, no doubt. There is also liquid.

As mentioned above the lightest alcohols in the boiler will congregate right at the condenser. So if your wash contains a tablespoon of methanol it will do the vapor / liquid conversions right at the condenser.

Surely the vast majority of reflux columns hold more than a tablespoon of liquid!!!!

With the methanol/heads you do indeed throw out a bit of good ethanol
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Ben »

Ok, some measurements are in order, I haven't done this math in a while so if something is wrong someone should correct me.

Assuming a 3" column with a 60" height that is 424 cubic inches, or 6.95 liters.

Lets assume that what's in the column is pure methanol, it probably isn't, its sort of best case.

Methanol is 1.202kg/m^3 at 65°c (just above its boiling point). 6.95 liters = .00695 m^3. .00695/m^3 x 1.202kg/m^3= .0084 kg = 8.4g.

So you have 8.4 g of vapor in your column.

At 20 c methanol is .7913 g/ml so in this hypothetical column, that makes 10.6 ml. A tablespoon is about 15 mils. So assuming you had no packing in the still, and you could purge everything that wasn't vapor you could potentially have 2/3 tablespoon of methanol vapor in your column.

Now lets back down the empty column assumption, and instead assume that column is packed with marbles (because they are the easiest to do the math on). The porosity of any group of spheres is 23%. So now you are down to about a 1/6th tablespoon of pure methanol vapor in your column.

Could make further assumptions about what is going on in the boiler but there is enough violence in there from the boil I would expect sufficient entrainment not to be able to use the volume, unless you had a very small relative amount of liquid in the boiler.

Lets not forget, the fores are mixed with a good percentage of ethanol, water, and "stuff", and most of that is more expansive than methanol.

So no... Can't fit that tablespoon of fores in your column. Not even close.
Last edited by Ben on Mon Dec 06, 2021 6:15 pm, edited 4 times in total.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by shadylane »

Ben wrote: Mon Dec 06, 2021 10:31 am I also get a precursor few drops of an odorless flammable liquid well before the head starts coming up to temp, not sure what that is. I just let the fores go for 20-30 minutes, smells like acetone, gets thrown out. Once the solvent smells go away I turn down the defleg water and run.
I hear what you're saying.
There's some of that in a sugar wash, but a lot more from a mash.
I've seen liquid dipping out the PC before the pot was hot enough boil.

Posting same time as Ben
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Ben wrote: Mon Dec 06, 2021 5:42 pm Ok, some measurements are in order, I haven't done this math in a while so if something is wrong someone should correct me.

Assuming a 3" column with a 60" height that is 424 cubic inches, or 6.95 liters.

Lets assume that what's in the column is pure methanol, it probably
So no... Can't fit that tablespoon of fores in your column. Not even close.
In that packed column is also liquid. How much liquid?

Have you personally run a reflux column?
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by shadylane »

LWTCS wrote: Mon Dec 06, 2021 5:44 am
As a general rule, we are simultaneously coming to temp, shifting alcohol into the column and allowing the lowest boiling constituents to occupy the highest available space prior to taking product.
Here's what I'm thinking.
Reflux stills heated with an internal electric element take a significant amount of time before all the boiler charge is at the same temp. Way before everything is hot enough to boil, there's localized boiling above the element making vapor.

The time spent "stacking" the column is actually about getting all the wash uniformly hot enough to boil.
Since there isn't enough space in a column to hold a significant amount of vapor, it's best to have a slow take off to make room for the rising vapor.

Postin wit dr
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

shadylane wrote: Mon Dec 06, 2021 6:41 pm
LWTCS wrote: Mon Dec 06, 2021 5:44 am
As a general rule, we are simultaneously coming to temp, shifting alcohol into the column and allowing the lowest boiling constituents to occupy the highest available space prior to taking product.
Here's what I'm thinking.
Reflux stills heated with an internal electric element take a significant amount of time before all the boiler charge is at the same temp. Way before everything is hot enough to boil, there's localized boiling above the element making vapor.

The time spent "stacking" the column is actually about getting all the wash uniformly hot enough to boil.
Since there isn't enough space in a column to hold a significant amount of vapor, it's best to have a slow take off to make room for the rising vapor.

Postin wit dr
Ummmm, no. Lwtcs is exactly right.

The fluid in the boiler is all the same temperature. It is either below boiling temperature, at boiling temperature, or it is boiling. If it isn't boiling nothing is going on.

The myth of evaporation being meaningful below boiling temperature is a fairytale.
You can take all the time you want heating it up slow. Imo that is wasted time, but it is certainly your time to waste.

You can sit and wish, but your wishes don't make booze.

Once it starts boiling the lightest stuff (fores) TEND to come off first, but it takes a bit of time and energy for all the fores to come out of the wash.

So, I suggest you bring it up to boiling, pull off some fores, boil a bit longer and see if you have more fores to remove.
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by shadylane »

drmiller100 wrote: Mon Dec 06, 2021 6:55 pm

The fluid in the boiler is all the same temperature.
Grab a long temp probe and do some measuring. :wink:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Setsumi »

Looking at articles describing methanol behaviour in stills.... those articles that states methanol is present throughout the run.... i think constituents are released throughout the run, some are more concentrated in certain parts but that is how i see it. A longer stabilizing time in a reflux column would help to compress the different fractions but will not seperate all 100%... again this is described in theory and most see it in practice.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Setsumi wrote: Mon Dec 06, 2021 9:17 pm Looking at articles describing methanol behaviour in stills.... those articles that states methanol is present throughout the run.... i think constituents are released throughout the run, some are more concentrated in certain parts but that is how i see it. A longer stabilizing time in a reflux column would help to compress the different fractions but will not seperate all 100%... again this is described in theory and most see it in practice.
Well, sure.

If I fart in bed, next week part of that fart is in my living room. Could a person measure it??? Sure!!!

But it would be easier to measure under my covers when I farted than a week later downstairs!!!!
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

shadylane wrote: Mon Dec 06, 2021 8:46 pm
drmiller100 wrote: Mon Dec 06, 2021 6:55 pm

The fluid in the boiler is all the same temperature.
Grab a long temp probe and do some measuring. :wink:
Measure what?
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Setsumi »

drmiller100 wrote: Mon Dec 06, 2021 9:56 pm
Setsumi wrote: Mon Dec 06, 2021 9:17 pm Looking at articles describing methanol behaviour in stills.... those articles that states methanol is present throughout the run.... i think constituents are released throughout the run, some are more concentrated in certain parts but that is how i see it. A longer stabilizing time in a reflux column would help to compress the different fractions but will not seperate all 100%... again this is described in theory and most see it in practice.
Well, sure.

If I fart in bed, next week part of that fart is in my living room. Could a person measure it??? Sure!!!

But it would be easier to measure under my covers when I farted than a week later downstairs!!!!
I have not read academic text on farts yet, I probably not look for it either.

But regarding Shadys question there is much reason to support a stabilizing period in a column - as hoby stillers found it helps stack the majority of fractions.

That said, you will never boil off the fractions one by one because the constituents in the run forms azotropes. It can be measured, most here will attest to tasting heads and tails in a badly executed run. We call it smearing but it is just that the run failed to separated the constituents to the taster,s ability not that the vapour from the boiler misbehaved. Is it beyond hoby distillation? No, it is the principles that influence distilation, commercial or on hobby level - in theory and in practice.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Fletching »

shadylane wrote: Mon Dec 06, 2021 6:41 pm
LWTCS wrote: Mon Dec 06, 2021 5:44 am
As a general rule, we are simultaneously coming to temp, shifting alcohol into the column and allowing the lowest boiling constituents to occupy the highest available space prior to taking product.
Here's what I'm thinking.
Reflux stills heated with an internal electric element take a significant amount of time before all the boiler charge is at the same temp. Way before everything is hot enough to boil, there's localized boiling above the element making vapor.

The time spent "stacking" the column is actually about getting all the wash uniformly hot enough to boil.
Since there isn't enough space in a column to hold a significant amount of vapor, it's best to have a slow take off to make room for the rising vapor.

Postin wit dr

A very interesting concept Shady. Sure got me thinking, as I have a 5500W element that stops dead center of my boiler. I’ve always wondered if a smaller element performed “worse” than an Ultra Low Watt Density one that took up more surface area. The thought that an electric element should be cranked up slowly, as to not concentrate vapor temps around the element made sense to me, but I had to test it.

So I went to the garage.

As stated, I have a 5500W element that is just long enough to extend to the dead center of my 15.5 gallon boiler.

For this test, I used 6 gallons of water, as I am not brave/dumb enough to do an open boiler test with wash/low wines, and don’t have enough ports on my boiler to do a closed test. I used a long digital temperature probe for measurements. I measured data from 5 different points in the boiler, marked North, East, South, West, and Center. My element enters the boiler from the south as a reference. I took each measurement at 3” below the surface level, marked on my probe, and did this in 5 minute increments up to the boiling point. See my results below.

A3A3F3BE-7C09-43A6-937E-1003DBDD70CB.jpeg

Based on my findings, I did see a difference in temperature at different measurement points in the boiler throughout the whole experiment. However, I did notice that the temperatures got much closer after the water started to boil excessively. This would tell me that once the water started to boil, it mixed the liquid much better in the boiler, giving it a more uniform temperature.

Additional information:
• While doing this experiment, I noticed that the water just above and around the element started to boil a couple of minutes before the rest of the boiler caught up.
• This was done with water, which may not be a good enough representation of wash/low wines in an actual run.
• I wasn’t able to test this too far into the boil, as my hands started to get burned by the steam as I took measurements.

So after this experiment, my thoughts would be that though it is true that the temperature in a boiler is not the same throughout upon starting up, it doesn’t take long once the liquid is boiling to develop an even boil (I saw this time to be about 3-4 minutes with the water).

Let me know what you all think, and if anyone has enough ports on their boiler to test this during an actual run, I would be curious to see the results.

-Fletching
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by The Baker »

But it would be easier to measure under my covers when I farted than a week later downstairs!!!!

Your significant other will give you an instant and accurate opinion.

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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Ben »

drmiller100 wrote: Mon Dec 06, 2021 6:39 pm
Ben wrote: Mon Dec 06, 2021 5:42 pm Ok, some measurements are in order, I haven't done this math in a while so if something is wrong someone should correct me.

Assuming a 3" column with a 60" height that is 424 cubic inches, or 6.95 liters.

Lets assume that what's in the column is pure methanol, it probably
So no... Can't fit that tablespoon of fores in your column. Not even close.
In that packed column is also liquid. How much liquid?

Have you personally run a reflux column?
Yes, as mentioned above 2 plate 4", pretty much exclusively these days. Which has nothing to do with what the column holds. The liquid volume is small enough to call negligible, but even if it wasn't it would be math beyond my level.

If you don't believe boiler temps vary wildly think about your hot water heater. As you draw hot water what is coming off of it doesn't automatically get colder as the boiler fills with cold water, it stays about the same. Strange, my tap water is about 58°, but my hot water will come out at 130 until the heater is empty... then it gets real cold real fast. It is not strange its just fluid mechanics. The same holds true in your boiler, until you actually hit boiling; then it takes a little time to stir up and the gradient becomes much smaller.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Ben »

It occurs to me that the elephant in the room on Shadylane's theory is the latent heat of vaporization. It takes a lot more energy to force a boil of (vaporize) any given liquid than it does to heat it up. By bringing the entire charge up we may be forcing the lighter distillates out because the kettle has become sort of energy rich. The light stuff will be boiling out rapidly, the entire mass is far above its vaporization temp. As it vaporizes energy is consumed, cooling the charge, forcing the heavier stuff to stay in place. We further push this by having a constant precipitation of energy hungry cooled liquid dropping back into the still. That stuff that is falling out of the dephleg is also cooling the vapor, forcing anything that doesn't have enough energy back down. IE you get better cuts when you run slow and don't overdo the heat input.

In petroleum engineering school we did distillations of crude oil, its very different from what we are doing. In petroleum distillations the fractions separate at a very broad temp range, 36°c to 750°c so its easy to tell what is coming off of the still at any given point, you could use a simple still and make several highly concentrated cuts, the crude would just stop boiling between fractions. This wasn't true for some of the lighter solvents, they tended to come off in a smeared mess. We are dealing with the light stuff, it would be nice if this was as easy as the heavy petroleum distillates. But it is what we are trying to mimic, we are trying to force the boil to be just hot enough to take off what we want.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Ben wrote: Tue Dec 07, 2021 8:28 am
drmiller100 wrote: Mon Dec 06, 2021 6:39 pm
Ben wrote: Mon Dec 06, 2021 5:42 pm Ok, some measurements are in order, I haven't done this math in a while so if something is wrong someone should correct me.

Assuming a 3" column with a 60" height that is 424 cubic inches, or 6.95 liters.

Lets assume that what's in the column is pure methanol, it probably
So no... Can't fit that tablespoon of fores in your column. Not even close.
In that packed column is also liquid. How much liquid?

Have you personally run a reflux column?
Yes, as mentioned above 2 plate 4", pretty much exclusively these days. Which has nothing to do with what the column holds. The liquid volume is small enough to call negligible, but even if it wasn't it would be math beyond my level.

If you don't believe boiler temps vary wildly think about your hot water heater. As you draw hot water what is coming off of it doesn't automatically get colder as the boiler fills with cold water, it stays about the same. Strange, my tap water is about 58°, but my hot water will come out at 130 until the heater is empty... then it gets real cold real fast. It is not strange its just fluid mechanics. The same holds true in your boiler, until you actually hit boiling; then it takes a little time to stir up and the gradient becomes much smaller.
2 plates in a column does not equate to reflux. Does your still send some liquid back down the column? How much fluid do both of those plates hold?

In a real reflux column the amount of liquid is significant and is what I was discussing.

Yes, i will agree a pot still run in reflux will not consolidate heads.

Hot water heater are pretty simple. Google!!!!

Again if the wash ain't boiling you are not distilling yet!
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Fletching wrote: Tue Dec 07, 2021 8:07 am .

-Fletching
Viscosity is a thing. The hotter the water the easier the molecules bounce around.

Also if you heat the top of the water amd don't stir the bottom can stay cold.

This has nothing to do with distillation as distillation can't start until the wash is boiling.
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Setsumi »

Ben wrote: Tue Dec 07, 2021 9:04 am It occurs to me that the elephant in the room on Shadylane's theory is the latent heat of vaporization. It takes a lot more energy to force a boil of (vaporize) any given liquid than it does to heat it up. By bringing the entire charge up we may be forcing the lighter distillates out because the kettle has become sort of energy rich. The light stuff will be boiling out rapidly, the entire mass is far above its vaporization temp. As it vaporizes energy is consumed, cooling the charge, forcing the heavier stuff to stay in place. We further push this by having a constant precipitation of energy hungry cooled liquid dropping back into the still. That stuff that is falling out of the dephleg is also cooling the vapor, forcing anything that doesn't have enough energy back down. IE you get better cuts when you run slow and don't overdo the heat input.

In petroleum engineering school we did distillations of crude oil, its very different from what we are doing. In petroleum distillations the fractions separate at a very broad temp range, 36°c to 750°c so its easy to tell what is coming off of the still at any given point, you could use a simple still and make several highly concentrated cuts, the crude would just stop boiling between fractions. This wasn't true for some of the lighter solvents, they tended to come off in a smeared mess. We are dealing with the light stuff, it would be nice if this was as easy as the heavy petroleum distillates. But it is what we are trying to mimic, we are trying to force the boil to be just hot enough to take off what we want.
Maybe i do not undestand you correct but it seems you describe distilation based on boiling points and that you can get pure concentrations... this may be true if you have 2 compounds with a very large difference in boiling temps. But you should consider Raults and Daltons laws in ethanol distillations. I am not so clued up but one says vapour temp and liquid temp should be the same while the mixture will have a different bp than any one of the constituents, the other say vapour contains the same mol combination than the mixture.

But i agree it may seems that a reflux column disrupts these laws to a degree... but only to the degree that it changes the constituents in the boiler through negative feedback. If the take off keeps high abv the return to boiler changes in consentration of the constituents that is in higher concentration. But chemistry is WAY out of my league.
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by Fletching »

drmiller100 wrote: Tue Dec 07, 2021 9:49 am
Fletching wrote: Tue Dec 07, 2021 8:07 am .

-Fletching
Viscosity is a thing. The hotter the water the easier the molecules bounce around.

Also if you heat the top of the water amd don't stir the bottom can stay cold.

This has nothing to do with distillation as distillation can't start until the wash is boiling.
Above, you said:

“ The fluid in the boiler is all the same temperature. It is either below boiling temperature, at boiling temperature, or it is boiling. If it isn't boiling nothing is going on.”

So I heated up the water, showing that temps were different before boiling, at boiling, and while boiling. Also noted that water started boiling directly above the element first.

So please tell me how my post is irrelevant if it addresses the very things you were talking about.

Then, in this post, you said:
“Also if you heat the top of the water and don't stir the bottom can stay cold.”

One post you say that temp in the boiler is always the same and in another post you say that it will be different if you don’t stir.

Maybe I misunderstood what the discussion was about, but I thought it was about finding whether varying boiler temps while heating the still with an electric element played a larger part in waiting to pull fores/heads than charging the column did.

Was this not the original question in this thread?
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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by shadylane »

drmiller100 wrote: Mon Dec 06, 2021 10:02 pm
shadylane wrote: Mon Dec 06, 2021 8:46 pm
drmiller100 wrote: Mon Dec 06, 2021 6:55 pm

The fluid in the boiler is all the same temperature.
Grab a long temp probe and do some measuring. :wink:
Measure what?
The temperature gradient inside the boiler.
Above the element the wash will be boiling, while below the element the wash temp can be several degrees cooler.
If your boiler has an agitator, try turning it on and off, to see what effect agitation has on the boil.

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Re: Equalizing a column or getting everything in the boiler upto temp.

Post by drmiller100 »

Setsumi wrote: Tue Dec 07, 2021 10:11 am combination than the mixture.

But i agree it may seems that a reflux column disrupts these laws to a degree... but only to the degree that it changes the constituents in the boiler through negative feedback. If the take off keeps high abv the return to boiler changes in consentration of the constituents that is in higher concentration. But chemistry is WAY out of my league.
This is the magic of the charts. For any concentration you can look up the temp, for any temp you can look up the concentration.

A reflux still is simply a bunch of boiling and condensing one on top of the other over and over. Note in the charts at each end the lines come together. It is really hard to get 95 percent, and it is really hard to drive that last 1 percent alcohol out of the boiler.
Methanol will generally tend to come out of the wash quicker than ethanol, but to get that last one part per billion takes a lot. And is probably a waste of time forest of us.

A packed column reflux still run in full reflux will absolutely tend to collect the light stuff at the top. That is the whole point of a good reflux still.
It also keeps the flavors and aromas out of the product unless you run it at less than 95 percent product.
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
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