Dephlegmator or Shotgun - That is the question

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zapata
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Re: Dephlegmator or Shotgun - That is the question

Post by zapata »

Now, to bring it back OT. Somebody better at math than me can use the above to objectively tell OP if a shotgun design dephlegmator will be any better than his current jacket design simply from a purity perspective. But at best it will be in the fraction of a theoretical plate range. Assuming he has the current jacketed design, and not the older cross tube design? I would intuitively say a shotgun design would be better than old cross tube style. I'm not so sure on the jacket version.

From a practical perspective, properly routing the product condenser and having separate control of the reflux condenser would likely have as much practical effect as the proposed upgrade. IOW, simply "upgrading" the condenser is likely to only offer small improvement, and there are likely other improvements that offer more bang for the buck (like doubling the packed height for example).
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Re: Dephlegmator or Shotgun - That is the question

Post by acfixer69 »

Thanks for that Thermopedia link it has lots of other stuff of interest. CM runners are only looking for the partial reflux and now that I see it written of course the phase change is the HETP shell and tube is the right tool. Design as required for individual needs.
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Re: Dephlegmator or Shotgun - That is the question

Post by thecroweater »

decoy wrote:final performance is governed by their design and construction and more so the operators competence. :roll:
True that but it is a given that each design requires knowledge and experience to achieve that designs optimum result, had I read Salties link before posted I would not have repeated the information that was already better put. I'm not promoting CMs by my post but simply trying to clarify what I read as conflicting information in some posts and trying to show the OP in more layman like terms that the deflagmator refers to the application not the design of the apparatus with a little background to the terms used :thumbup: .
The OP I understand is running CM in a pretty similar configuration to my plates column (with packing in lieu of plates) . Also occasionally add a packed module to my plates column to run as a CM. it's a bit tricky to run as I have a tuna can sized deflagmator so getting good separation while maintaining a high proof takes some playing about and other than saying a larger RC would be handy I don't see really how you can improve on it.
So my advise to the OP would be to use a more efficient reflux condenser if he feels his proof is not high enough or more importantly his separation is not up to scratch. More efficient could just mean a longer tube and case or put two in there but changing the design to say a Graham may cause other problems like flooding. CMs ran well may get a better separation of tails and they are at least ran in a plate/packing configuration much much faster then your average joe reflux still like the bokka design or ultrapure set ups but it will be hard to beat the stet and forget efficiency of some of those designs. I have one that will get azeotropic ethanol all day any day but it bloody well takes all day as it have a take off restriction :lolno:
The OP could make up this design for his still head but might be more than a bit disappointed with that take off speed
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Very efficient but very slow reflux head
Very efficient but very slow reflux head
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Re: Dephlegmator or Shotgun - That is the question

Post by Saltbush Bill »

zapata wrote:My problem I guess is I've never seen an explanation of how that supposedly works, and I've searched a number of times. Thanks to your challenge, I found it today.
We all think and see things in different ways Zap, I don't really enjoy reading miles of technical stuff unless I really have to, to me it just seems common sense that, that's how it works.
zapata wrote: It's just a miniature column working on all the fundamentals of any reflux system.
Yep that's a nice simple way of looking at it.
I like simple, I'm just an old truck driver /machinery operator, not a rocket scientist.
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Re: Dephlegmator or Shotgun - That is the question

Post by Avo »

Avo wrote:To add to the confussion - the three? types of condenser, shotgun, dephlegmator & the Gatlin gun, they appear to be one of the same design. (Vertical tubes) Is one more efficient than the other for refluxing I asked.
The conventional end product condenser, such as the liebig, is now being replaced in the Chinese kits by just such a condenser, a 400/450mm dephlegmator or whatever you want to call it. :crazy:

In conclussion I would like to thank you all for your most interesting comments; they were most appreciated. I shall re-read over and absorb your comments and wisdom. :wink:
I thought I would publish some older quotes I have found which I really like; giving credit to the authors.
They condense (pardon the pun) and simplify things for the newcomer/novice. I can see the logic for the slang term of 'Shotgun' applied (if it must be used) this being a longer version of a short dephlegmator reflux condenser, with less tubes and used for the final product.

This topic and contribution of it's authors has helped me decide what to purchase for my upgrade.
I shall be buying a 200mm 8 tube dephlegmator for my reflux, and a 450mm 6 tube 'Shotgun' dephlegmator
for my final product condenser. In conclussion the pricing/quality inc' p&p on the well known Chinese site; according to the reviewers, is amazing.
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Re: Dephlegmator or Shotgun - That is the question

Post by Avo »

decoy wrote:The topic appears to be going of track.

Avo wanted to improve his still and in the OP he assumed a Dephlegmator was a specific type of condenser not a specific role a condenser plays in the process.

Avo if you post a pic of the condenser you interpreted to be a Dephlegmator, we could then comment on preference.

TheCrowEater is correct the shotgun is a multi core or tube liebig condenser.
Understood and agree - Thanks
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Re: Dephlegmator or Shotgun - That is the question

Post by zapata »

thecroweater wrote: CMs ran well may get a better separation of tails
That begs proof. Failing proof I would love to hear detailed theory. The paper I linked above shows a dephlegmator (CM) getting less than 1 theoretical plate worth of purification. And if you read the paper the tested dephlegmator was almost 1METER tall! It also makes it pretty clear there is simple, counter current reflux based rectification happening, not some magic "CM holds back tails".

Tying it back directly to OP, maybe a better condenser would be called for if he can't hold full (or damn near) reflux. But you know what would hold back tails 100% better? An extra meter of packing, regardless of head management principle.
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Re: Dephlegmator or Shotgun - That is the question

Post by zapata »

Avo wrote: I shall be buying a 200mm 8 tube dephlegmator for my reflux,
Yup. Feel free to call it a shotgun as well if needing to describe it's design.
and a 450mm 6 tube 'Shotgun' dephlegmator
for my final product condenser.
So close. Just call it any combination of shotgun/product/final/condenser. Dephlegmator in this hobby really does mean it will only condense part of the vapor which would be a huge fail for a product condenser.
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Re: Dephlegmator or Shotgun - That is the question

Post by Avo »

thecroweater wrote:
decoy wrote:final performance is governed by their design and construction and more so the operators competence. :roll:
True that but it is a given that each design requires knowledge and experience to achieve that designs optimum result, had I read Salties link before posted I would not have repeated the information that was already better put. I'm not promoting CMs by my post but simply trying to clarify what I read as conflicting information in some posts and trying to show the OP in more layman like terms that the deflagmator refers to the application not the design of the apparatus with a little background to the terms used :thumbup: .
The OP I understand is running CM in a pretty similar configuration to my plates column (with packing in lieu of plates) . Also occasionally add a packed module to my plates column to run as a CM. it's a bit tricky to run as I have a tuna can sized deflagmator so getting good separation while maintaining a high proof takes some playing about and other than saying a larger RC would be handy I don't see really how you can improve on it.
So my advise to the OP would be to use a more efficient reflux condenser if he feels his proof is not high enough or more importantly his separation is not up to scratch. More efficient could just mean a longer tube and case or put two in there but changing the design to say a Graham may cause other problems like flooding. CMs ran well may get a better separation of tails and they are at least ran in a plate/packing

configuration much much faster then your average joe reflux still like the bokka design or ultrapure set ups but it will be hard to beat the stet and forget efficiency of some of those designs. I have one that will get azeotropic ethanol all day any day but it bloody well takes all day as it have a take off restriction :lolno:
The OP could make up this design for his still head but might be more than a bit disappointed with that take off speed


:thumbup:
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Re: Dephlegmator or Shotgun - That is the question

Post by Bushman »

This has turned out to be a great thread. I over simplified my explanation defining a dephlagmater as a reflux condenser and not mentioning specifically to a CM column. I would like to add to what Crow has mentioned about the operators use. Early CM stills did not allow for 100% reflux but as we have improved our designs it is attainable. Having said that I have only achieved a maximum of 94% where my VM I can attain 96. I very seldom do a neutral and as most of my runs are now AG runs so I run more for flavor than purity and shoot for 80 to 90%.
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Re: Dephlegmator or Shotgun - That is the question

Post by shadylane »

zapata wrote:

The results of the work reported here can be summarized
follows :
the dephlegmator has been confirmed to be suitable for
obtaining additional rectification of the vapour leaving
a distillation column;
the amount of this separation is generally around one
theoretical stage and is not very sensitive to the
temperature of the coolant, nor to its flow rate;
the mathematical model proposed, derived from the
Colburn and Drew theory, gives reasonable predictions
for all the variables involved and is relatively easy to
apply.

All you CM lovers rejoice, you really do get maybe almost an extra theoretical plate over LM or VM in an otherwise identical still.

In theory, a defleg might be equal to 1 plate
In practice, it ain't so :lol:
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Re: Dephlegmator or Shotgun - That is the question

Post by thecroweater »

Bushman is as usual spot on but to add more : Lots of guys get hung up on the percentage and that's ok as long as you don't loose sight of the purity. If you are getting azeotropic 95.63% that's great but what is really important is what's in the 4.37%. You can get immeasurably close to azeo and still have nasty contaminates and you can get say 91% that is clean as can be, no one is drinking 90+% ethanol so a neutral spirit should be the main aim. Before upgrading ask yourself why, do you think it can be cleaner or are you chasing proof? A bigger condenser may allow you to run a little faster but that can become a real balancing act between time and purity. We have no real way of telling with the data provided but it could be your still can do all you want it to with a lower take off rate and tighter cuts.
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Re: Dephlegmator or Shotgun - That is the question

Post by Setsumi »

looops wrong thread. no delete sorry
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Re: Dephlegmator or Shotgun - That is the question

Post by Setsumi »

zapata wrote:Disclaimer, yes this is way deep in the weeds for the OP, but I learned something fundamental today which doesn't happen all that often in the arrogance of old age.
Saltbush Bill wrote: This taken from another explanation and definition. "Vapor leaving the device has become concentrated in the more volatile components, while the condensate is richer in the less volatile components."
Maybe I have just misunderstood what this means.
http://www.thermopedia.com/content/691/" onclick="window.open(this.href);return false;" rel="nofollow
My problem I guess is I've never seen an explanation of how that supposedly works, and I've searched a number of times. Thanks to your challenge, I found it today.

"Mathematical model for process design and simulation of dephlegmators (partial condensers) for binary mixtures"
https://onlinelibrary.wiley.com/doi" onclick="window.open(this.href);return false;" rel="nofollow

All you CM lovers rejoice, you really do get maybe almost an extra theoretical plate over LM or VM in an otherwise identical still. (Though to be fair, a dephlegmator usually takes up just as much vertical space as 1 HETP or 1 physical plate, so it's easy enough to compensate)

Note, there is no indication that there is any magical suppression of tails/high boilers nor magical passing of more volatiles. It's just a miniature column working on all the fundamentals of any reflux system.
cave1987.pdf
good read on dephlags.
but it only deals with dephlags, no mention in realation to vm or lm so no edge on vm or lm only a description to understand cm better. or so I read.
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Re: Dephlegmator or Shotgun - That is the question

Post by zapata »

That's true, the comparison to LM and VM was my inference. A dephlegmator causes some degree of rectification. LM and VM have no dephlegmator, thus in an otherwise identical still would have some degree less rectification.

I don't see it as knock on LM or VM. I've never been a fan of CM, from a practical perspective. Kinda OT for here, but I am in the process of blank sheet redesigning all my stills. If a dephlegmator causes any rectification, I want to know it now so it can be modeled and designed around or dismissed as appropriate. I doubt I will end up with CM anywhere, but this really is a blank sheet reboot which requires questioning my assumptions and preferences. Up to now I really didn't know dephs can cause ANY purification, I suspect in practice it isn't a meaningful amount, see how many people have put thermometers on both sides of a flute's deph and read the same vapor temp. But I will dive deep, and if a dephlegmator really offers benefits to other designs I have kicking around, a dephlegmator it will be.
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Re: Dephlegmator or Shotgun - That is the question

Post by shadylane »

What design of defleg are you thinking about building
A tube and shell shotgun or a several feet of small coiled up tubing :?:
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Re: Dephlegmator or Shotgun - That is the question

Post by Evil Wizard »

I'm hoping someone can jog my memory. I recall on this forum seeing an old style condensor used for deflag that was a single tube in shell, like a liebig, except the inner tube was shaped to increase surface area.

Shaped how? Well i suspect it was built out of sheet copper, with a cone at the bottom,and then slid inside the wide shell. Water goes into the shell and vapor in the tube.

At my new job i have a continous armagnac still by SOFAC that noone has run in ten years, the guy who put it together is dead, and I'm not going to open the bolted gaskets to look inside.

Thanks boys.
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Re: Dephlegmator or Shotgun - That is the question

Post by Sulaiman »

zapata : as you are restarting from scratch,
you may want to consider something that I've been thinking about,

You can use a small reflux condenser (dephlegmator) with cold water,
or a physically larger condenser with warmer water.
One difference is the temperature of the condensate returned to the column,
colder condensate will mess up the temperature gradient at the top of the column,
So separation / fractionation will be poorer.

Just a thought... not tested yet.
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Re: Dephlegmator or Shotgun - That is the question

Post by Corsaire »

Evil Wizard wrote: Thu Aug 20, 2020 11:03 am I'm hoping someone can jog my memory. I recall on this forum seeing an old style condensor used for deflag that was a single tube in shell, like a liebig, except the inner tube was shaped to increase surface area.

Shaped how? Well i suspect it was built out of sheet copper, with a cone at the bottom,and then slid inside the wide shell. Water goes into the shell and vapor in the tube.

At my new job i have a continous armagnac still by SOFAC that noone has run in ten years, the guy who put it together is dead, and I'm not going to open the bolted gaskets to look inside.

Thanks boys.
You mean something like this?
viewtopic.php?p=6834790#p6834851

Iirc olddog used something similar but with reducers in his magic flute.
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Re: Dephlegmator or Shotgun - That is the question

Post by Evil Wizard »

Yes something like that. Any idea what its called?
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Re: Dephlegmator or Shotgun - That is the question

Post by zapata »

I believe that is often referred to as a lintel? Lintle? Seems I've seen a number of old european allembics like that, often the lintel is just an open topped shallow pan.
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