2 inch plated columns problems?

[Usge]

Happy Easter: More ramblings.

Not sure if this is the same thing you were saying...but,

1) A fractioning tube using only heat cannot be put under forced/total reflux like a compound reflux still can. The term you are looking for is equilibrium, ie., when the reflux/cooling from the top and the warmer rising vapor from the bottom form a temp gradient within the column and the vapor stacks up as fractions in the tube in order of volatility . This in turn creates a "pocket" or sweet spot where one can "carefully" withdraw the top/fraction without upsetting the balance ...such that the column continues to pump the highest purity (lowest temp) fractions to the top, as opposed to running them all together. In Complete Distiller, this was described as a tight-rope walker carrying 2 bags of potatoes (one on each arm). If you take a few potatoes at a time, he can adjust, and continue on. If you take a large bunch, or a whole bag at once...he will become unbalanced in such a way that he will fall.

Compound reflux, "forces"reflux/returned distillate from the top. This allows you to run "more" heat, such that with the additional cooling at the top, you can achieve higher "reflux ratios" faster than would be possible running heat alone. "Plate" wise...a flute has "4" literal plates at fixed heights in the column for distillate/reflux to "mingle" on under heat/reflux.. ....where as stuffing a longer tube with mesh...may have up to many times more worth of scrubbing power (in terms of "plates") to remove nearly every last hint of flavor/impurities. I would also suggest, the goals are somewhat different (ie., making azeotrope, vs making refined "flavorful" spirits). For azeotrope, you'd need a lot more plates. Something else to consider would be the section in Complete Distiller where they discuss the basic fractional tube...where they suggest that it can be run with faster take off rates.

The first Flute design used more of a traditional deplegmator...which was simply an internal liebig like condenser in the top of the head. My understanding was this design was not quite capable of running "full" or total reflux under higher heat levels (but otherwise worked well). There were some issues with the hole size in the plates as well, which were corrected in later revisions. But, as to one of your later points..I dont' think this flow issue had any bearing on the distillate taste (as I recall..they were getting really good results...even with less than optimal flow through the sieve plates. The shotgun dephlegmators are capable of holding the column under full/total reflux...even under higher heat levels, for extended period of time. And the way it's done is ...they hold it under full reflux until all plates are full, bubbling and give it time to stack a bit. Then, you reduce the water flow to the dephlegmator, and start allowing some portion of the vapor to come through. The same caveats from before (the tight rope walker and balancing act) would still apply here. There has to be a certain amount of flow/volume of vapor...to maintain enough reflux to keep the plates full and bubbling and maintain that volume/portion of higher purity vapor that you are taking off....."at the same time". This is an important point. And particularly in regards to flutes with "perf" plates; they require a certain amount of flow/heat/volume to keep the plates from weeping and operating properly. A bubble cap, has more flexibility in that it can run at lower pressures/volumes. That's what they say in the books anyway.

I'm no good at ciperin, but way I figure....If you take their figuring (math) for the optimal range of flow (vapor speed/heat) for a given column...and then figure out exactly how much distillate that "is" in regards to a "flow-rate", you've got some idea of how much "total" volume you have to work with. From there, if you subtract the volume needed for each plate, etc., you'll have an idea of the reflux ratio/rate needed to keep them full. And what's left would probably put you in the ballpark of what the max flow-rate (take off) you could achieve and still maintain everything. In regards to plate spacing...I just don't know. I do think that requires some further testing. However, in regards to the 2" column for this design....I think if you could eventually calculate everything "perfectly"...you'd STILL find that you'd be dribbling off runs, with long run times, etc. Whether or not you could get it fixed to where it didn't have the flavor issues, etc., would be another thing. But, frankly on a 2"....I think most people would probably just as soon stuff a bit of mesh up the tube and put a coil in the top and be done with it. Gotta stop now...my head hurting again.

[flyingdutchman]

Usge,
All said and done I suspect you are right in that

....I think if you could eventually calculate everything "perfectly"...you'd STILL find that you'd be dribbling off runs, with long run times, etc. Whether or not you could get it fixed to where it didn't have the flavor issues, etc., would be another thing. But, frankly on a 2"....I think most people would probably just as soon stuff a bit of mesh up the tube and put a coil in the top and be done with it. Gotta stop now...my head hurting again.

. I think i will fool around with some of the calcs to see what i came come up with and will post any results here. I appreciate all your help, information and effort on this subject. I suspect I owe you a couple of good scotches, or at least some asprin for the the headaches I have caused.

[devotus]

Great thread

[LWTCS]

Great thread

+1
Yes good to see more on this subject matter. Seemed like it needed more.
In general, its not really feasible for one member to take this stuff from start to finish as the budget , the build fatigue and the need for drinking stock usually trump the need to experiment.

Thanks from the community for pushing the 2" experiments along.

[flyingdutchman]

Hey this whole thing may lead nowhere but maybe its fun just to consider it? the chemical engineer at work says he will help out but the off taste worries him so he wants to know the other components in a common distillaion. I suspect the entire list would be huge and probably vary depending on yeast and other ingredients but from the parent site, the compleat distiller, and this threadhttp://homedistiller.org/forum/viewtopic.php?f=1&t=12350&hilit=tails+analysis I think I have the alot of the major ones covered. i have no clue if the rubber tire flavor is in this list. Did I miss any big ones?
TYPICAL
Acetone 56.5C
Methanol 64C
Ethyl acetate 77.1C
Ethanol 78C
2-Propanol 82C
1-Propanol 97C
Water 100C
Isobutanol 107.9 C
Butanol 116C
2-methyl-1-butanol 128.7C
Isopentanol 131.1 C
Amyl alcohol 137.8 C
Furfural 161C (322F

[flyingdutchman]

More questions,
In order to do the calculations I guess I need more initial data so for those of you have have built these here are some design questions for you.
1) Assuming you are watt burners what wattage do you run these at (1250?)
2) Since you run dephlegmators what is your target reflux ratio
3) What is your typical distillate collection rate (300 ml/30 minutes?)
4) As per Usge's previous post I am assuming 4 physical plates and a typical column height of roughly 24".

[Usge]

More questions,
In order to do the calculations I guess I need more initial data so for those of you have have built these here are some design questions for you.
1) Assuming you are watt burners what wattage do you run these at (1250?)

Dont' run 'lectric. Using gas, on stove top, through an iron grate. But, if it helps...it takes me about 1.5 hours to bring 5 gals to a boil.

2) Since you run dephlegmators what is your target reflux ratio

What I was shooting for was a take-off rate similar to a potstill (ie., a stream around 20ml per min). What I quickly realized was there simply was not enough volume to both maintain the column under reflux, and take off a "stream". So, I shot for a "dribble" take off rate, the thinking being that it would allow more to be used for reflux to fill the plates, etc. From there, I also tried just dripping off the take off rate (like a boka). So, I was managing my reflux ratio, based on the take-off rate vs heat to see what I could get and still maintain the column's stability/plates. I initially just wanted to be able to maintain a constant 65% or so...ie., for whiskey. More info under my response to question 3.

3) What is your typical distillate collection rate (300 ml/30 minutes?)

Most of my stuff is documented in the "new take on old design" ODs magic flute mk 2 thread. But, I''m gonna quote/repost some stuff here for sake of this thread/research, etc.:

First: One of the significant things about the redesigned 4" MK2 was that OD had created a tray-disabling system that could be built using common off-the-shelf parts. I wanted to quote this from his first trial using this system:

I have ran Flute Mk2 a couple of times now and fixed all of the wrinkles (leaks) etc, and I decided to try my current fermentation of UJSSM using the plate dissabling system in an attempt to achieve a 65ABV takeoff. I took of foreshots and heads with all plates engaged, restacked the column, and proceeded to take the hearts,I sampled he spirit using a spoon full of water and a few drops of alcohol from the parrot, it was nice and clean as usual with a nice creamy corn taste. I dissabled all of the plates except the bottom plate, and watched the ABV descend to the required 65%, I again tested the spirit with my usual spoon full of water and a few drops of alcohol from the parrot. The taste was crap gone was the clean corney taste, and the taste I was getting was not nice at all. I engaged all of the plates again, and back came the 90%ABV with that nice clean corn taste.

Some may like the ability to dissable plates in the column, and the system does work as designed, but from now on I will be running with all plates firing, for me the taste is better.

My first run data is here. I original designed/built my 2" to be "modular". This was my first run using "one" plate module (ie., the bottom one with the J-trap downcomer)

Just finished my first spirit run using the new 2 incher. 5 Gals of UJSM low-wines and feints at 45%. I think I've got to agree with OD's findings on this. The distillate was harsh and bitter. It started at 85%. I ran off about 9 pints and it dropped from 85% to 80% during that time. None of it was drinkable. So, all this is going back in the pot for tomorrow. Think I'll just run it off with my potstill head so I have something to put in my barrel (need to get that started soon).

Running it was a chore. Never could quite get it dialed right. It seemed if I even had "any" water trickling out of the top of the dephleg...the distillate would just stop. So, I had it where every now and again...it would dump some water out of the top...but that slowed the stream down to about 3 drops per sec. It was taking way longer than even my bok does. So, I tried upping the heat just a bit...so I could try and get some flow to the dephleg and still have some kind of output. Didn't work.

I'm a little disappointed and obviously have more to learn. Not sure how to get the dephleg straightened out. The only way to get a "stream" output of distillate on this was to turn the water to the dephleg "off". If the water was even remotely on, it would cut the stream down a dribble/drops. But, I'm not giving up. Going to add another plate soon, and give it another go. In the meantime..if anybody has any suggestions?

Heres' the data from the first run:
500ml fores
3:02 pint 84%
3:30 pint 84%
4:07 pint 84%
4:38 pint 84%
5:10 pint 83%
5:45 pint 83%
6:25 pint 83%
6:52 300ml 82%
7:23 pint 81%
7:43 300ml 80%

Shut down at that point.

This documents the trouble early on that I was having with the water/flow system (maintaining balance/flow between the delpheg and the product condenser). This looks like a pretty typical "thumper/pot" run. It appears the caps, etc. were working, I could hear them gurgling through the product condenser. Unfortunately, I had/have no site glasses so...have no data on what the plates looked like under load. Flow-rate was all over the map given my issues with the deplegm but calculated as an average comes out to 14ml per min.

This was my second run, using 2 plates, and running 5 gals of "wash":

200ml 77% head temp 182F (went up to 190, had to adjust water flow)
200ml 79% 182F
200ml 79% 182F
200ml 81% 182F (temp rose to 191F, adjust water)
200ml 74% (made note here that I was having trouble controlling temp)
250ml 77% 192F (emptied the parrot and re-equalized for 15mins down to 180F)
100ml 80% 186F (would not flow at 180, temp going to 192F, cannot control temp tails coming)
150ml 67% 204F
100ml 45% 206F (re-equalize one more time, for 15 mins)
200ml 40% (won't hold temp anymore)

Very hard to run wash,...just not enough alc. Notes from this run indicate the distillate wasn't that bad, but had smeared heads that were very sharp. Tails were not as bad. I have not time/flow-rates for this run, but given the notes here about all the adjustments, etc., probably was all over the place.

Here's the 3rd run on 4 plates (plus notes on the run at the time) 4.5 gals low-wines (3 gal UJSM, 1 gal mixed barley, .5 gal water to bring it to 40%:

240ml of fores 93% (Vapor temp 178F, Water temp 112F)
1 - pint 92.5% V=179+, W=130F
2 - pint 92% V=140+ (distillate streaming now) W=140F
3 - pint 90.5% V=179+, W=145F
4 -300ml 90% (emptied parrot)
5 - pint 90% V=180F, W=160F (water flow out of balance, restabilized)
6 - pint 91% V=180F, W=140F (distillate back to dribble)
7 - pint 90% V=180, W=150F
8 - pint 89% V=180, W=160F (adjusted water flow up slightly)
9 - pint 91% V=180, W=150F
10 - pint 89% V=180, W=160F (re-equalized for a couple mins)
11 - pint 91% V=179, W=120-160F (tails)
12 - pint 85% V=186, W=178F (can no longer hold temp, turning off water and flushing out rest of tails)

The good news was...my new dephlegm was very responsive. Slight adjustments, which happened quickly, could bring the proof back and stabilize things. The bad news was there was a small leak right at the join of the needle valve into the dephlegm that was causing some surging. I tied a rag around it, but could still here it sucking at the rag. The distillate was coming out it in "lots"..ie., drip, dribble, stream, pause...repeat. I'm guessing this was probably because of the leak. But, despite the variances, it managed to hold/stabilize along the way for good bits of time. Which brings me to the other bad part...despite finally getting some flow-rate, etc., dailed in...the run still took over 9 hours start to finish. And the distillate was rather disappointing —I got about the same flavor range as I do on a potstill...ie., lots of heads, a couple middle jars, then tails. The only difference was...at 90%...the heads are intense, the middle was scratchy/bitter, and the tails taste chemical. Could be it just needs to be cleaned some more. But, I experienced similar results running my boka in potstill mode. So, I don't think my bubble plates are working like they should. (ie., I'm not seeing any heads/tails compression).

So, here you have the abv showing from 4 plates working (ie., up in the 90s). But, instead of light, smooth, flavorful/corny distillate...I get very sharp heads, very scratchy/bitter dry middle and chemical tasting tails.

Here's next run on 4 plates 5 gals of 8% all barley malt AG:
Notes document starting at full heat, reducing to "med" (about 1/2) bringing it under full reflux with the deplegm. It was held under full reflux for 15mins then water flow to deplegm was reduced till I got "drips".

At that point, Vapor temp (V) was 172F and the water temp (W) was about 100-102F. I dripped off the fores like this...very slowly. Water got out of balance here and there and I had to make a few adjustments.
I took 120ml of fores at V=177F/W=150F (2-3 drops per sec). From there it went like this:

1 - 200ml V=178 W=160F 90% (adjusting heat up slightly to Med-Hi and water flow down to stream distillate)
2 - 200ml V=180 W=140 90%
3 - 200ml V=180 W=150 86% (adjusted water to maintain stream)
4 - 200ml V=184 W=160 85%
5 - 200ml V=186 W=160 82% (re-equalized for 15 mins, then reduced water flow, raised heat to get it to flow again)
6 - 200ml V=182 W=160 87%
7 - 200ml V=186 W=168 70% (Flushing tails out, turned water off)
8 - 300ml V=204 W=190 40%
9 250ml (emptied parrot)

Total run time...start to finish was about 5.75 hours.

Again, very hard to run wash or low-abv still charge. There just isn't enough alc to feed the column/plates AND take off distillate at any sort of flow-rate. Despite the deplegm and plates, the abv falls like a rock through the run and it very hard to maintain stability. The second comment was/is that I was getting about the same amount of heads/tails as an average potstill run, which is not what I was expecting. I was expecting a lot of "compression" where there would be a short stack of heads, then a long/wide cut of homogenous hearts within a very small range of abv, then it would start to rise (onset of tails) and tails would happen fast in small amount of volume. My experience seemed to show that the same "flavors" of a linear run happen in the same locations "regardless" of the proof you run it at. These experiences would become the basis of my Linear Flavor Theory, which I posted in this forum a while back. You take some distillate flavor that occurs in a run and then run the proof up to 90%. What was once, tollerable, or even pleasant, suddenly becomes biting, stinging, hacking, etc.

Some people I respect a lot...suggested that the problem must be my ferments...since it seems to occur under differing circumstances/stills,etc. So, I spent the next year, starting from scratch with my ferments..experimenting with yeast, temp, etc. Some was better than others, and I certainly learned alot about how to keep them happy. But, it never changed my observations. And just to confirm it, I dug out my old 4 plate tube and slapped on my new depleg (which works much better and is easier to control) and repeated a run. The results were not any different. I also went back and studied up on various topics, etc. to see if there was something I was missing. In the interim, OD, the father of the flute, and KS, the apprentice who had the most experience building them left and/or went into background. There have been "many" flute builds since then. The one "common" thing is that people trying to build 2" versions have documented same issues I have had and that the distillate simply doesn't taste good.

Summary:
My guess would be that this is from "smearing". And my further guess is, this is from trying to make a 2" column do what a 4" one does (ie., pull enough vapor to fill and run 4 plates..while at the same time take off distillate like a cow pissing on a flatrock.). It ain't gonna happen. The most "consistent" run I had above...(abv didn't vary too much ) was the one that took almost 10 hours. I think this is simply inherent to the beast (of a 2" pipe") volume wise. There were other issues I dealt with too that could have had further impact on this....ie., the lack of alc abv volume to start with (the still charge). There just isn't enough alc in a 5 gal charge of wash to make this work. I make note here that this is primarly what people with "flutes" do....single run wash up to 90% for clean, flavorful distillate. Along with my 'Flavor theory", there are certain flavors that happen during a linear run cycle. The more spread out these are, the more good stuff you are going to find somewhere between the two ends. But, a "short" run through...in a column where the entire run could be contained in one cycle through plates...isn't going to produce anything but smeared distilalte beginning to end. And this is what I think the "rubber tire" is. It's heads/tails/ass and all in one big smeared mess...run up to 80 or 90%. Others seem to indicate what I have "not" found in any of my experiments: that they run 5 gals (or small amount of initial abv) and get same results...only smaller amount of good stuff. What I see is a threshold, where the entire thing is just smeared together (not unlike trying to run a 4liter potstill).

This is "no" getting around the limitations of "volume". I dont' think putting plates and a deplegmator in a 2" column is going to change the fact that it's still 2". At least that's what I've come to conclude through over a year of research into it...which admittedly isn't much compared to some....nor at the same level/depth. If you run a 2" (whatever") you will be spending a lot of time sitting beside it. And the higher reflux ratio you want to run, the more time you are going to spend. Further, the higher the reflux ratio, you'll need more starting abv (still charge) to work with to ensure good results. What the exact answers are I can't tell you. But, I can tell you it's more than 5 gals of wash

That still leaves the question(s) of whether or not one could optimize the plates/distance/type, etc...such that one could achieve better heads/tails compression and/or less smearing than I did. But, even after you got it all dialed...my guess is the volume issue is one you won't be able to change (ie., you'll still be dripping the run off over many hours).

[devotus]

A fantastic post that I wish I's read 6 months ago. Respect for taking the time to post such a detailed response.

All advice regardless of plated column or not should point the newbie away from diameters less than 3 inch, yes 3 inch and above cost a lot but the pain in the butt that smaller diameters are aren't worth the saving of a $100 or so.

[flyingdutchman]

Usge,
Thanks for the great description. I strongly believe that your conclusion is precisely what the problem is. I seriously doubt the problem ever was your fermentation. This issue has been too repeatable across too many 2 inch columns and never seems to appear in an 4 inch one (which again points right back to your conclusion). I will work out the calculations (with some help) and post them here with what i hope will be a clearer explanation of the process than some of the texts I have been trying to decipher. I hope this will be a benefit because once it is posted and explained I see no reason why it cant be applied to 3, 4 or bigger diameter columns and help optimize or at the very least see the effect of altering different parameters in the column.
Devotus,
I absolutely agree from the standpoint of ease of use/volume of distillate etc that 3 inch or bigger is going to be much easier to use. Still for some interested in trying it out, i think a 2 inch diameter column has its place. Granted it will have all the problems you point out and you are correct in that compared to the bigger diameter column it may be a pain the butt to use. Still I think Tony Ackland does cover column diameter here http://homedistiller.org/theory/refluxdesign/diameter and painstaking shows his calculations herehttp://homedistiller.org/calcs/equations Take one look at his calculations and you can see why I am trying so hard to get the process guy here to help me lol.
here are his conclusions

Generally, a 2" (50mm) diameter is an ideal size to use. This will happily run from 750W up to 2500W without any trouble. If in doubt, go for 2".

Its this amount of energy that you put in which will determine the rate at which you make and collect the distillate. If collected at the condenser at say 95%, it works out roughly to the following figures. If you run a reflux ratio of 4 (e.g. return 40 mL for every 10 mL you keep - typical for SS scrubbers) - then the second figure is the flowrate you'd expect to collect at ...

1000 W = 52 mL/min (max, no reflux) or 10 mL/min (if RR=4)
1500 W = 78 mL/min (max, no reflux) or 16 mL/min (if RR=4)
2000 W = 105 mL/min (max, no reflux) or 21 mL/min (if RR=4)
2500 W = 131 mL/min (max, no reflux) or 26 mL/min (if RR=4)
3000 W = 157 mL/min (max, no reflux) or 32 mL/min (if RR=4)
3500 W = 183 mL/min (max, no reflux) or 36 mL/min (if RR=4)
4000 W = 209 mL/min (max, no reflux) or 42 mL/min (if RR=4)

Please don't think I am just trying to just contradict you because that is definitely not my intention I do agree with what you are saying. There is no way a piece of 2 inch will ever "piss like a race horse".I just think that maybe some people starting out might look at the price of 3-4 inch copper, plus the tools to work it, not to mention perhaps it he increased difficulty to solder it and never even try it out which would be a shame cause its a lot of fun building these and learning to use them.

[Usge]

Actually, (a clue) there "was" one instance of a 4 incher having this issue (see my post above). OD, when he disabled all the plates save the lowest one...experienced same/similar thing. HOWEVER: the first experimental Mk2 he built...was a "2 plate" version. You can find it in the "my still" forum (search). It was shorter and used 2 of the bubble plates with weir downcomers, and had a newly designed deplegmator module in the top of the head, and used the new 3-way T valve for water flow. This one achieved similar results as the older design 4 plate....or at least..appeared to have not had issues with off-tasting (overly smeared) distillate. I think I'd look at those 2 things together for a clue into the issue. (ie., I would think this would mean, it's not simply the number of plates (which should mainly adjust the overall abv) but the plate volume, vs column volume (ie.,including distance between plates).

here: viewtopic.php?f=50&t=21354

One interesting comment he makes that offers another clue :

The only points I noticed, were I got better results in not going past 2/3’s full on the keg – half full keg for Bourbon/Wiskeys etc were best . Any more then this I was getting surging and gave not so good results – mixed bag in the cuts.

My guess is this is because of the longer 2" run up to the 4" plate section...so it required a bit more volume/air in the pot to allow it to draw off without smearing it before it got to the plates. (ie., the other side of the volume issue (velocity). So, it would seem that the "volume" issue might also includes the "pot" or at least how the head is connected to the pot, the shape of the pot, etc. if you want to add even more calculations into it (ok...head hurting again).

[Usge]

A fantastic post that I wish I's read 6 months ago. Respect for taking the time to post such a detailed response.

All advice regardless of plated column or not should point the newbie away from diameters less than 3 inch, yes 3 inch and above cost a lot but the pain in the butt that smaller diameters are aren't worth the saving of a $100 or so.

Devotous, thanks for the kind words. I think the thing you need to keep more in your mind is not just girth for overall volume but also about flow. (ie., take whatever design you are thinking of and fill it with water from bottom up...where does the water speed up, where does it slow down?). Where the water/vapor slows down..there is more time to separate. Where it speeds up, there is more chance of smearing. A wise old goose once asked the question about the design of traditional potstill heads......where do you think it ort to slow down?

Sometimes it is what it is devotus. Could be other limiting factors. I can't run more than 5 gals off my stove-top (and I'm really pushing it with that). So, I'm rather limited by my "starting" volume as well.

[devotus]

Good point usge. Space to work in is probably the only factor I could think of that would make me recommend a smaller than 3 inch reflux column. Apologies for my slightly off topic interjection. I'll not clutter this good thread up any more than I already now have.

2 inch plated columns tend to produce less than desirable distillate eh?