Continuous distillation flute?

[mash rookie]

Instead of a boiler, what about closing the bottom of a four inch flute twelve inches below the plates and install an electric element?

The thought being that guys could run their large 55 gallon washes with much less power in a continuous fashion.

Feed rate of cleared wash into the column and spent wash take off below would be easy to synchronize to a rate of desire collection of tails.

How would we get rid of the heads?

Could they be vented off farther up the column than the product take off where they would still be vapor as a higher alcohol?

If kept at a perfect temperature doesn’t a dephlag almost act like a heads heart separator if the heads were allowed to continue up?

I.E. place an inverted funnel above the dephlag chamber and add two feet of ¼ inch tube. While the higher alcohols are still trying to rise, ethanol vapor will seek the path of least resistance and head for the product condenser?

Make any sense? Okay, beat me up guys!!

[rad14701]

With a continuous still you cannot make cuts unless you run a true fractioning column where you pull off fractions at different plates... That is getting beyond hobby distillation, at least in my opinion... Doing continuous distillation runs for stripping is one thing but for final product it gets tricky because everything is there all the way through the run...

[airhill]

Actually there was a continuous still on I think the Swedish forum that extracted both heads and tails. I have not permission to post the diagram but I will try to describe it.
The boiler was very low and long (A rectangular box) on it were two columns the first tall and open to the boiler the second shorter and not open to the boiler. Mash was introduced about halfway down the first column and on the top of this column was a Bok under a reflux condenser, the bottom bok plate was connected to the middle of the second column via a solenoid valve. Heads were contained in a heads trap at the top of the second column alcohol from the bottom of the second column. I suppose if you were picky you could describe it as an slightly intermittent continuous still.

[Pelson]

Hi,

I've also been thinking about a continious still sometimes.
Indeed it would save a lot of place (large boiler vs small one). I don't think however that, apart from heat losses due to the size of the boiler, you would spend that much less energy. After all, you do have to heat the whole batch up to boiling point... (even if it's only drip by drip).

I think Rad's quite wright about this whole thing not really being that 'hobby' anymore.

I immediatly thought of the drawings in my book of industrial chemistry, on the part of oil cracking.
You could in fact just build a large destillation tower (flute-style). I think it would have to involve a whole bunch of plates, and I think you should take off products on all of them (to make shure the equilibrium in the column is sustained). In that way you get rid of the heads (a the top of the column - lower boiling point) and your tails (at the bottem - higher boiling point).

It would make a nice industrial still though!
Maybe an idea for when we run out of oil and everything is fueled by ethanol

[Smokehouse Shiner]

Hey MR, I see your not getting much response here. (no offence to those that have responded). Continuous distillation has been discussed several times just since I've been here and in the end, well, nobody actually does it. Probably a reason for that. Except Manu. So he'd be the man to research and talk to if your serious. He's known as Stainless Guy here. I have no interest in the subject so have nothing to add to the conversation, just thought I'd give you the heads up on Manu. He's a smart dude and has built a working continuous stripper. Wouldn't we all like to have one of those.

[rubber duck]

It does lean toward the commercial end as Rock said but it would be nice to save power and space. Also there is the challenge of making it work, gear head's love a challenge.

I'd like to see it done just for the doing of it.

[heartcut]

A flute with feed in on the 2nd or 3rd tray (using the bottom trays as a rectifier) and liquid takeoffs and liquid thermometers at each tray would be a kissing cousin to a refinery distillation column and, with what would probably be a lot of development, could be set up to take different boiling point products from the tray liquid takeoffs. The only vapour overhead would be foreshots. This fall, I should have enough time to find out. Cheaper and faster would be nice, and if I can't make it work, it'll still be a flute. Edit- looks like Pelson said pretty much this same thing- no offence, just should have read the whole thread.

[blanikdog]

Hey MR, I see your not getting much response here. (no offence to those that have responded). Continuous distillation has been discussed several times just since I've been here and in the end, well, nobody actually does it. Probably a reason for that. Except Manu. So he'd be the man to research and talk to if your serious. He's known as Stainless Guy here. I have no interest in the subject so have nothing to add to the conversation, just thought I'd give you the heads up on Manu. He's a smart dude and has built a working continuous stripper. Wouldn't we all like to have one of those.

+1 Smokehouse.

[WalkingWolf]

Hey MR, I see your not getting much response here. (no offence to those that have responded). Continuous distillation has been discussed several times just since I've been here and in the end, well, nobody actually does it. Probably a reason for that. Except Manu. So he'd be the man to research and talk to if your serious. He's known as Stainless Guy here. I have no interest in the subject so have nothing to add to the conversation, just thought I'd give you the heads up on Manu. He's a smart dude and has built a working continuous stripper. Wouldn't we all like to have one of those.

+1 Smokehouse.

Seems to me to be approaching semi commercial operation also. Not what this forum is about. See rule 9.

She's only commercial if you give her money. If you watch for free it's simply a peep show.

[Smokehouse Shiner]

Hey MR, I see your not getting much response here. (no offence to those that have responded). Continuous distillation has been discussed several times just since I've been here and in the end, well, nobody actually does it. Probably a reason for that. Except Manu. So he'd be the man to research and talk to if your serious. He's known as Stainless Guy here. I have no interest in the subject so have nothing to add to the conversation, just thought I'd give you the heads up on Manu. He's a smart dude and has built a working continuous stripper. Wouldn't we all like to have one of those.

+1 Smokehouse.

Seems to me to be approaching semi commercial operation also. Not what this forum is about. See rule 9.

She's only commercial if you give her money. If you watch for free it's simply a peep show.

That's the ticket WW. I understand the desire to want to pursue contionuous stillin for completely non commercial reasons. And if anyone wants to do it just cause they like a challenge and tinkering and have the time and money,I say go for it! But honestly I believe the same result can be achieved simply and more efficiently with a bigger boiler. I'll bet that just about every stiller here wishes their boiler were just a little bit bigger for stripping runs. But getting past the common range of boiler size for hobbyists can and will be perceived as just reaching for volume by the general readership of this forum at least. Continuous stillin will be considered the same. Pretty sure the law would not care if your boiler were 15 or 50 or 500 gallons as long as they wanna bust you. And I'm also reasonably sure that Joe Blow Johnny Law will not even come close to understanding how the proposed continuous still works and won't really care. Just gonna make you out to be a more technologically advanced bootlegger. My point is that for the most part we're all outaws. Like it or lump it. Don't sell and don't tell.

[rubber duck]

I don't see the difference between a continuous still, or a rig with a preheater like I have, or a 50 gallon fermentor or a 15 gallon fermentor 4 times a month . Your running the same mash your just not reloading the boiler. Besides a continue rig is going green and you can't argue with saving the planet right.

Rule 9 means don't be a dumb ass, no selling, no commercial. I don't see how a small scale continuous rig violates that rule, everything on this forum can be used to break rule 9.

A continuous rig is a interesting challenge, I'd like to see a simple design that works and really works.

[Pelson]

Well indeed, it's just a challange... maybe not even to actually build, but just to design...

Since I'm having examinations right now, I could use my brake-time (which sometimes does exceed my study-time) to think of a little concept

But, RR, I don't readily see how to make a simple design that realy works... But I'll try to think of one! Ha! Just for the heck of it!

Cheers

[olddog]

There is a design here, if you really want to build one. http://journeytoforever.org/biofuel_lib ... meCh7.html" onclick="window.open(this.href);return false;" rel="nofollow


OD

[rad14701]

There is a design here, if you really want to build one. http://journeytoforever.org/biofuel_lib ... meCh7.html" onclick="window.open(this.href);return false;" rel="nofollow


OD

The first column still I built was loosely based on that batch still design in that article...

Again, continuous operation isn't hard to do as long as you accept the fact that making proper cuts is an issue when making potable spirits... I'd love to have one to experiment with for stripping...

[mash rookie]

I don't see the difference between a continuous still, or a rig with a preheater like I have, or a 50 gallon fermentor or a 15 gallon fermentor 4 times a month . Your running the same mash your just not reloading the boiler. Besides a continue rig is going green and you can't argue with saving the planet right.

Rule 9 means don't be a dumb ass, no selling, no commercial. I don't see how a small scale continuous rig violates that rule, everything on this forum can be used to break rule 9.

A continuous rig is a interesting challenge, I'd like to see a simple design that works and really works.

That is what I am talking about RD.

Her are my thoughts, If the commercial guys are doing it why cant we do it on a smaller scale and do it better? We have the patients to tinker, experiment and the courage to fail as many times as necessary.

Old dog has done such a great job of designing a small scale commercial type still that it makes me ask what the next step is?

Thank you for the link OD, I will check it out. I have been looking at picture and theories online including oil distillation designs.

What is your next challenge OD?

I am not ready by a long shot to try to build a continuous still. Still working on my flute build. (pictures soon)

After a little more research maybe I will throw out a couple design of ideas for you guys to chew on.

THANK YOU to those that offer positive input on this subject. Lets see where we can take it.

MOD EDIT: Offensive remark removed

MR

[mash rookie]

After looking at that link OD provided it got me thinking about OD’s new design with his valves for returning product for additional reflux.

What if at the top plate the liquid there was taken off to a vessel? Would the gasses that continue to the condenser be mostly heads?

It would be interesting to know what is being produced at each level of a plated still early in a run where all compounds are present.

Lets say that if a guy had a six plate column and a needle valve at each one, he might be able to draw a small amount of distillate off each plate without collapsing the reflux flood. Would there be a flavor difference? ABV difference? Heads difference?

It may be that OD is closer than we think with his design to having a continuous still if operated differently.

Unlike a batch system where we remove heads first then collect everything as hearts and tails, a continuous feed system would have consistent ratio in the column of heads,hearts and tails throughout the entire run. The question will be where, when and how do you collect them.

When I run my UJSSM I collect pretty deep into the tails for flavor. I think the hearts and tails part on a contunuous still would be easy. The nasty heads another story.
MR

[olddog]

When I run my UJSSM I collect pretty deep into the tails for flavor

You wont with a Flute, hearts stop automatically. If you turn off the dephlegmater to collect tails, you get around 300ml from a 25lt wash, as tails have been compressed.


OD

[rad14701]

If you collect from the plates then nothing goes out past the dephlegmator... All fractions would be taken at plate levels... This would be a totally different concept than the flutes... The only common concept would be the plates...

[mash rookie]

When I run my UJSSM I collect pretty deep into the tails for flavor

You wont with a Flute, hearts stop automatically. If you turn off the dephlegmater to collect tails, you get around 300ml from a 25lt wash, as tails have been compressed.


OD

OD
That is exactly why I am excited about this line of thinking. Your flute design already does a great job of separating hearts and tails.

When thinking from the point of view using your flute with a constant flow of wash introduced within the plate tree. There will always be heads, heart and tails in the mix. The hearts go up, tails go down.

What do we do with the heads if they are there on a constant basis because we are introducing fresh wash on a constant basis?

Two separate condensers? Elevation location based on temperature? How the heck could we get the heads to continue up and not exit with the hearts?

[olddog]

MR, just build yourself a scaled down Coffey still, it will do all of what your asking.

OD

[Pelson]

Well... that would be a nice project to build a scale-sized thing...

Well, MR, what you could do (and what's actually been done in the coffey still) is build a column with a large number of plates (20+ or so).
Then you would have to measure the temperature of each plate at a run, and then you would get a nice seperation of your products according to boiling temperature.

As you say, the you could remove products from the plates (but: at a rate slow enough not to majorly disturb the equilibrium) and so you could actually strip off everything and get pure ethanol (well: the azeotrope off course), and then higher you'd get off the methanol and low boiling products (heads).
Lower on the column there would be the tails (higher bp products).

I suppose this could work, however, it would take LOTS of time and LOTS of investment and investigation...

I think the coffey still is one of the best ways to construct a continuous still... and one has to admit that we can't really make it much more efficient.
(the alcohol-hobby is been going on for ages now, so I don't think they'll come up with a design that's shockingly new and does things never thought possible before...)

But it could be a good challange to try and convert the coffey-still into a small-sized scale model...
I don't suppose however that it would be really profitable... If you use the same system and blow steam in at the bottom, and use a pump to get your wash in... hmm...

dunno dunno... we could however change it a lil' bit

[heartcut]

If the overhead vapour temperature is adjusted just right, the foreshots will be the only vapour going into what's conventionally used as the main product condensor. The trays and reflux would condense the other cuts.

[mash rookie]

. All fractions would be taken at plate levels... This would be a totally different concept than the flutes... The only common concept would be the plates...

I agree. Except that the heads should be allowed to continue up and be condensed by the product condensor. the thinking is that heads are a constant because of the constant feed of wash.

If the overhead vapour temperature is adjusted just right, the foreshots will be the only vapour going into what's conventionally used as the main product condensor. The trays and reflux would condense the other cuts.

The dephlagometer is the product condensor in this type of running mode.

Besides a continue rig is going green and you can't argue with saving the planet right.

Not just green. Being electric it will be safer to run then a propane rig where open flames are always a risk. Possibly low enough amp draw to be run on a standard 120 V 15 amp circut making it simpler for an average guy. Heat control would be more acurate as well. That would be critical for this to work.

The speed of wash introduced and spent wash taken off would determine ABV remaining in the spent wash and the ABV at the top.

My observations running my simple CM column the fore shots and heads came off in the low 170,s As the temp rose to 180- 185, I take off my booze. Because it is such a poor design, I would try for high ABV by keeping my temp at the head as low as possible. The product stream would stop if it dipped down in the low 170,s after the heads were taken.
My point being, with the dephlag able to control head temp, an element with a MK controler controling the boil necessary for different washes, This just may be doable.

[azeo]

This may be of interest, it's a packed column I believe but no reason why plans couldn't be modified to suit a flute I guess.

http://www.ferromit.com/continuous%20still2.html

I think the same site may have been posted here from time to time. Opinions seem to vary, but I don't think there are that many equivalent designs out there.


Something else that may be useful or interesting is this excerpt ..

Textbook-2ndsect 1-82.pdf

(20.59 MiB) Downloaded 370 times

[guittarmaster]

I hope there is an engineer or fellow chemist reading this that can contribute to what I'm about to post as I'm only about 90% confident in what I'm about to state. But, Isn't evaporation a state function of the of the system in question? If so then you won't save much if any energy by running one.

Taking the system to be evaporation of the mash the boiler, isn't the relationship dt/dp? In short for a given pressure (inside the boiler & still at different plates) the energy required for evaporation is basically a constant. This means your not saving any energy.
Eg. it will take water 2260J/g to transition the liquid-gas phase change ; for 100% pure ethanol the phase change is 838.3 J/g. This is why water always boils at 100C and alcohol at 78C. Any mixture of the two should have a phase change somewhere in between those two (actually limited by the azeotropic mixture) We see this by the temperature difference & gradation relative to purity in a reflux column.

I would think the best way to reduce the energy required for distillation would be by running a vacuum still, but again, could be wrong here.
Second method would be to fill the boiler half way up, run mash through both your delph and product condenser and have it rigged to discharge into the boiler or onto the lowest plate; however I don't believe anybody would save much money doing it this way because it seems the relative time to heat room temperature water to boiling is much quicker the the time to boil all of the water away.

I COULD be wrong, this still could work a little differently than I"m thinking.... I believed the advantage of a continuous still was simply increased productivity by being able to distill around the clock, non-stop, no "recharging" time. Could be wrong. haven't' studies the sketches yet, YET...( it's late here.)

Otherwise one *COULD* offset the energy and water usage of a hobby still by simply filling up the bathtub with the discharge water from the delph and condenser. Throw some bubbles in it and let the misses enjoy herself!! LOL I mean, you gotta clean up sometime ... when I ran my 2.5 gallon pot still I distilled in the kitchen and collected the discharged hot water into the sink and washed the dishes in in!

GM

[guittarmaster]

But it could be a good challange to try and convert the coffey-still into a small-sized scale model...
I don't suppose however that it would be really profitable... If you use the same system and blow steam in at the bottom, and use a pump to get your wash in... hmm...

dunno dunno... we could however change it a lil' bit

something to chew on:

http://www.youtube.com/watch?v=j1rq1oqkPcs" onclick="window.open(this.href);return false;" rel="nofollow

also, check out OD's evil twins, they were based on the coffee column but modified for the home distiller and single batch.

[heartcut]

I hope there is an engineer or fellow chemist reading this that can contribute to what I'm about to post as I'm only about 90% confident in what I'm about to state. But, Isn't evaporation a state function of the of the system in question? If so then you won't save much if any energy by running one.

I think the main savings would be exchanging the heat from the stillage and cooling systems to the feed in.

[sterlingchap]

Taking the system to be evaporation of the mash the boiler, isn't the relationship dt/dp? In short for a given pressure (inside the boiler & still at different plates) the energy required for evaporation is basically a constant. This means your not saving any energy.
Eg. it will take water 2260J/g to transition the liquid-gas phase change ; for 100% pure ethanol the phase change is 838.3 J/g. This is why water always boils at 100C and alcohol at 78C. Any mixture of the two should have a phase change somewhere in between those two (actually limited by the azeotropic mixture) We see this by the temperature difference & gradation relative to purity in a reflux column.

GM

The basics are easy to explain:
in a conventional pot still with no fractionating (or "plate") column nothing is produced until the entire pot contents are raised to their boiling point - roughly 93C for a 10% ABV wash. With a 2KW heater, a 10L pot will take nearly 30 mins to get there....... a 60L (~12 Gallon) pot will be about 3 HOURS.

Only then does distillate (maybe 55% alcohol) start flowing. If "visitors" arrive unexpectedly, you switch off, let if cool down and have NO distillate.... just an electricity bill!

No "visitors" arrive, so now things get interesting..... that 2KW heater now vapourises pot contents at roughly 1g per second. The vapour goes up the spout, hits the output condenser and emerges as roughly 50-55% ABV distillate. You may get about 1800mls of 50% distillate from 10L of wash before the "tails" start coming over and you call it a day. 1% alcohol, of the original wash's 10% alcohol, stays in the pot.

Oh yes... collecting that 1800 mls of distillate is going to take another 30 minutes (~1g per second, remember?) Or if you use a 60L pot, about 3 more HOURS!

And your total electricity usage is 2KWH overall (12KWH for a 60L pot).

For a well-insulated pot and still, using a bigger heater merely reduces the time taken to complete the process.

If you add a fractionating column you will still use the "warm up" heat to bring the wash to the boil, but there things change.

Like this:
The first gram of vapour starts climbing up the column. At some point this vapour becomes so cool that it must condense (into a somewhat more concentrated alcohol/water solution). In doing so, the heat of vapourisation is RELEASED into anything that the vapour is contacting when it condenses. The column wall, the packing or any liquid which isn't quite at its boiling point. A balance is established where condensed liquid falls down the column, and vapours rise up it. Near the bottom of the column (higher temperature) any liquid present will contain LESS than 10% alcohol, and any vapour present will contain >50% alcohol - starting with a 10% ABV wash. For a long, efficient column, near the top there will be NO liquid below about 95% alcohol, and all vapour will be >95% alcohol.

And all of the heat used to get that alcohol vapour to the top of the column has been conserved.

Only now do we "throw away" the heat which keeps the output vapourised (with an output condenser).

In theory, the only heat we throw away from this output condenser is that required to vapourise the ALCOHOL content of the entire wash (around 1L for a 10% ABV wash of 10L). That heat requirement is roughly 800 x 838 = 670400 Joules or about 5.5 minutes-worth of 2KW heating.
So you can turn down the heat, or increase the output flow (and REDUCE the time required overall).

With a continuous-operation still we merely remove the requirement to heat the entire pot contents up to boiling point. We heat ONLY enough wash to produce the vapour which we can handle at any one time. Once heated and stripped of it's alcohol, it is discarded.
Bit-by-bit.

And if "visitors" call by, we just switch off and resume when they've gone (almost...)


It is the advantage of low heated mass and the conservation of heat (identical to a fractionating pot still thereafter) via the condensation of only the desired concentration of distillate which makes a continuous still techically appealing.
It is not, IMHO, incompatible with all of the pot still developments which have gone before...... it is merely the next stage of distillation art.

What about "heads"?
Does anyone really believe that removing heads continuously will prove to be an insurmountable problem?
Anyone wanna offer me long odds?????

A great topic mash rookie.
I suspect that great satisfaction awaits the successful experimenter!

Chap


Oh yes, before some wag points out that heat is also lost from the "reflux" condenser....... that's true. Because the purpose of a reflux condenser is to reduce the length of fractionating column required to concentrate a given mass of the vapour removed from its top.
So from an efficiency standpoint, a reflux condenser is, well, er ........ Bad News.

[mash rookie]

No, I don’t think it is going to be that tough to remove the heads. By using OD’s flute in a different manor than intended. The dephlagometer ( How do you spell this) should allow for very precise head temperature control.

I don’t want to use steam as that would require a separate boiler.

All in one unit. Electrical element, gravity feed input, float controlled fluid level and a simple valve for tails take off speed will determine spent wash ABV.
An MK controller to keep boiler temp where necessary for wash ABV to boil. The dephlag will keep precise temp for separation of the heads.

Now, where do we take off the product?

I will post a couple of sketches of my thoughts in a few days. Thanks for the interest guys. Keep it coming.

[sterlingchap]

CASUAL READERS TAKE NOTE: these are "off the wall" ideas and NOT proven design redcommendations!!!

My own thoughts so far.....
If we arrange a thermal differential over a distance at the top of such a continuous column, and withdraw our distillate from the LOWER part of that differential distance, "heads" will preferentially (lower BP) be constrained away from our target juice..... think maybe of a TWO-boka system with, say, 30mm of ss-packed space between them (to promote the differential). Heads congregate in the top boka, distillate in the bottom one.

I suspect that LM will, at least initially, be easier to manage than VM.

For me, steam (triac-controlled steam generator) represents the easiest-to-control heating method for such experimentation. The jury's out regarding "production" designs!


So, the lower part of the column is essentially an SS-packed "heat exchanger" where steam feed condenses and falls, and wash feed evaporates and rises. Then a suitable length of SS packing above all this to fractionate the vapours (or none if flavoured distillate wanted rather than Neutrals). Then atop this the fractionating "double boka" idea.
Each boka has its own needle valve to control heads and distillate take off rates (which can be calculated in advance....)

I don't really understand the logic behind their entrenchments, but we can expect this sort of discussion to raise the hackles of some here. They seem to resent any form of foward movement unless it's done with oars [pulsed production] and NOT propellers [contimuous production]. And reciprocating engines instead of new-fangled turbines........

Let's hope we don't get shot for daring to ask "why not"?
Chap