2" perforated plate experiments

[guittarmaster]

As the guy who was going to be cut my kegs has been unavailable, I've been spending the time experimenting on plate design for my 2" vodka and gin column. Here is al ink to the video I put together with some of my initial results. I'll update the thread later tonight with the details. Hope you enjoy.

http://www.youtube.com/watch?v=rfbUW1mfp-Q" onclick="window.open(this.href);return false;" rel="nofollow

p.s. sorry for the low quality video... it was done my old crappy cell phone.

[Barney Fife]

Damned interesting method to study plates and their behavior. Thanks for the ideas! What we need now is the find out the volume of distillate being return via the defleg at a given power level to know what the replenishing rate will be, and can then calculate the ideal size, amount and number of holes for the plate.

A thought just struck me that to have more than one perforated plate working exactly the same as the other, each plate will require different sizes and numbers of holes. The uppermost plate will need to most holes as it see the most reflux, while we'll need fewer and fewer holes as we head toward plate number one. The first plate sees the most energy, but the least amount of returned distillate(reflux), so to keep it "wet" it will require fewer, and/or smaller, holes, while the upper most plate sees the least energy, and the most returned distillate.

Interesting....

[guittarmaster]

"good science inspires good science"
------my p-chem professor.

A thought just struck me that to have more than one perforated plate working exactly the same as the other, each plate will require different sizes and numbers of holes. The uppermost plate will need to most holes as it see the most reflux, while we'll need fewer and fewer holes as we head toward plate number one. The first plate sees the most energy, but the least amount of returned distillate(reflux), so to keep it "wet" it will require fewer, and/or smaller, holes, while the upper most plate sees the least energy, and the most returned distillate.

I haven't thought of it like that, but I think this line of thought is on to something..... I just wanted to experiment and test the ideal # of hole in a perforated 2" plate in a somewhat quantitate way. I decided to use 3/32" holes from the Kentucky shinner video in the flute talk thread(and was the smallest drill bit I had that would work on metal).

To answer your question; heat capacity for Cu is 0.385(J/g•K) Thickness of 0.0010668 meters, L-G transition state of water is dH=40.66, dS=109.1... ethanol, dH=42.3, dS 109.8 Clausius-Clapeyron equation is searchable on wiki... low on time.... it's a simple thermodynamics problem using heat capacity of copper, the environmental temperature, the surface area inside the still, column internal pressure, heat from the boiler, area of holes, mass of copper, Clausius-Clapeyron equation, mass of condensate above the plate, length of column. A phase change diagram as a function of the alochol-water azeotropic concentration and pressure would be useful too. Buy having dH and dS and the Claus-Clap equation this becomes an extra credit problem for the chemical engineers and other chemists with more time on their hands that I currently (senior year),


Experimental parameter:
*each plate was allowed to reach thermal equilibrium by waiting 5min after noticing the rate of steam through them became steady.
*2πr^2 ..... 2π(2.53cm)^2= 20.26cm^2 = 0.68oz = ~4.1 teaspoons of calculated standing fluid above the 2"plate. (volume of vapor bubbles aside) which was slowly poured onto the plate after plate warmed up.
* the 2" section of pipe was placed over a 12"diameter pot with a lid in which a 1/2 inch hole was placed (to replicate the column I am building)
* I poured 4 teaspoons (as calculated above) onto each plate slowly after thermal equilibrium was reached and timed how long each plate held the water until the vaper was either splashed out or fell through.
* each run was first done on high heat, and then repeated on med hi, and then medium if the plates allowed.
• Heat source was an 8" electric stove range.
• plates were lightly held into place using flour paste so that if back pressure became too high the plate could flip.
•

Results:
12 holes of 3/32" diameter:.... 0.0826sq.in total hole area....
• made a quiet whistle sound like a tea-kettle on med heat and was louder on high
• held water fro 5min49s on med
• violently splashed water out in a few minutes on high and flipped the plate onto an angle

16 holes..... 0.110 sq.in total hole area....
• made a very slight whistle sound on med after equilibrium and quiet whistle sound on high heat.
• noticed water starting to form on the plate around the holes. after three extra minutes of waiting most of the plate was slightly wet and an occasional gurgle sound of reflux could be heard.
• On medium heat the plates held water for over 8 min when I dropped my phone and lost the stopwatch function. I let it continue for a few more minutes and got bored and moved on.
• On hight heat the plate held water for several minutes and bubbles quite well.

30 holes.... 0.206 sq.in total hole area...
• would not support water on med
• supported water on med-hi heat for 10-15 sec
• supported water on high heat for roughly 3min
• no whistling noises

60 holes.... 0.413 sq.in total hole area....
• only held water on high heat for 10-15 seconds.
• had to pour hot water onto the plate as cool or warm water would run through the plate.(assuming it condensed the vapor and fell through)
• might work alright on a keg boiler with no restriction (in a boka or other column)

discussion

This experiment was designed to test how well varying the number of holes in a 2" perforated plate would preform in the column that I am building....a double column similar to ODs evil twin build. This experiment certainly would benefit from other members recreating it using a keg boiler and not restricting the vapor flow. This would give more accurate results of performance while distilling.

Another fruitful and similar experiment could be holding the # of holes constant and varying the pattern on the plate, or by keeping the ration of area that is holes constant and varying the size and number of holes.

Conclusion

I feel the 16 holed plate performed the best of the four I tested. It self-wetted the plate with a small amount of liquid, and preformed over the largest power range between collapsing condensate and high heat.

[Kentucky shinner]

this was awesome man.. Thanks for the insight.. I would love to see you try this with the 1/8" holes... thanks again.
KS

[guittarmaster]

I would love to see you try this with the 1/8" holes.

I'll have to get another drill bit... but that can be arranged ... I gotta go to the hard-ware store to get the last part I need to finish the controller box for my electric keg. I'll try to pick it up the bit then... It'll probably take me a a few weeks before I'ld have time AND results to post. In the mean-time, If anyone has a few inches of 2" and enough scrap to make a plate, by all means experiment and post your results for the best experimentally determined 2" plate configuration!!!!

[aqua vitae]

Maybe try bubble plates. Perforated plates suits the purpose better in the analyzer column which is fed continuously with wash from the top. It's meant for the plates to empty or else it would choke.
Bubble plates are a bit more tricky to build but they will never run dry. You'll get more vapour/liquid contact too as there will be more smaller bubbles then in a simple perforated plate.

[todd54]

Excelent video. I've read through the string, thankyou for the effort to explain your theory in a simply straight foward way. If you missed points reading you saw it in the video. Thanks.

[guittarmaster]

I have a full assortment of drill bits now... I'm thinking of testing 1/8 & 1/16th inch holes. I've got the copper plates cut out and ready to start the experiments... just need the free time... and maybe better camera.

[loneswinger]

This is a good experiment, however, there are some things you need to know: limitations on the experimental capacity.

1. The pressure drop of vapor flow across a perforated plate holds the fluid height on the plate (for the most part). There are some good approximations/calculators out there if you know the vapor flow speed, fraction of open area, and vapor viscosity. All of which are known of course for water/ethanol.

2. At a given boiler power, to a good approximation, the same amount of power is supplied to each plate. (Better approximation if column is insulated). The mass of the copper is not a variable of interest once equilibrium is established.

3. Both water and ethanol have about the same enthalpy of vaporization when expressed in kJ/mol. So about the same volumetric rate of vapor flow will be seen at each plate.

4. Water vapor is a lot less dense than ethanol vapor and as a consequence, the pressure drop across a plate where the vapor is rich in water will be lower than the pressure drop across the plate when the vapor is rich in ethanol. So for a given plate and power, water vapor will not be able to support as much liquid on the plate as ethanol vapor. The effect is significant, from memory the pressure drop from water vapor is about 1/2 the pressure drop from ethanol vapor.

5. In full reflux and equilibrium, whatever travels up between plates as vapor, travels down between plates as liquid reflux. This is simply a statement of mass conservation. However, the enthalpy of vaporization when expressed in kJ/kg is a lot higher for water than it is for ethanol. Therefore the lower plates rich in water see a lot less liquid reflux (lower mass transfer rates) than the upper plates rich in ethanol. If the plates support the liquid than the lack of reflux is not a problem, however if they are weeping significantly than the ones seeing less reflux are more likely to run dry.

As a consequence of 4 and 5, the lower plates need to have a smaller open area (fewer and/or smaller holes) than the upper plates (not because of any 'power seen by plates' effect). Furthermore, if you design your plates for a particular water-ethanol profile up the column, they may not work well at different concentrations: some plates might dry up as the boiler is depleted in ethanol and the vapor stream becomes more rich in water. Conversely, if you add a stronger low wines charge than you designed for, the lower plates may be more likely to flood. For this reason, perforated plates are not normally used in batch distillation since you can not design them for a broad range of water/ethanol/power configurations.

All of this information is out there if you are willing to browse chem-E and fluid dynamics papers and texts. The experiments you are doing are fun and you may learn a lot by doing them, but they have already been done and published. If you want to continue them anyway, be sure to adjust the water/ethanol concentration in the vapor stream.

Cheers,

-Loneswinger

[Samohon]

Interesting video... Thanks again man...

[guittarmaster]

I like the imput so far.

All of this information is out there if you are willing to browse chem-E and fluid dynamics papers and texts.

Is there any one resource you could give a link to? I"m interested in seeing these experiments through till completion and not to brag, but I got a great grade in P-chem.

I'm thinking that the experiment needs to be done twice for each single plate,,,, once with plane water and again with alcohol at the 96% azeotrope and average their performance

Also thinking that I'll have to run experiments testing downcommers too.

Also thought of comparing the plates with a scrubber packed column.

could get a good, calculated estimate and experimentally confirmed idea for (x)hole on bottom plates, of (x)size... (x)hole on middle plates, of (x)size... and (x)hole on top plates, of (x)size... get the "idea" plate configuration for a 2" plate column, and compare it to the packing... It'll be either myth confirmed or busted..

[coppercreature]

I've been dying to see a similar experiment - SS scruby packing vs. a flute model ala KS or OD's. If you could get the flavor profile and throughput of a 4" plate where the vapor is bubbled up through 4 plates, without the cost of 4" copper, we'd have a winner. Could scrubbies in a 2" column equal to 4 HETP provide the same richness of flavor as 4 perforated plates with downcomers in a 4" column? Would a 2" perforated plate design with downcomers be able to compete with a flute?
Maybe design an experiment with a split batch of Rum or UJSM and a 2" column - one with 30cm of scrubies and one with 4 perforated plates with downcomers?

[coppercreature]

OK kids. I'm taking the plated column plunge. Can't really call it a Flute, but maybe a Kazoo? Finally made it through all 94 pages of Flute talk, then they go and change the design on me
Not here to talk about theory, throughput, or bubble caps. Mostly here to discuss the construction methods and tips for 2" plates that I used.

First, sourcing the plates: http://cgi.ebay.com/Sheet-347-Perforate ... 43a5adbb73 Holes are .055 in Diameter and are on .090 Centers 30% Open.
I'd say these are too thin for any 4" build, but worked pretty well for the 2". I'm hoping 347 Stainless is OK, from a health and safety standpoint.
To make the round cutouts, rough cuts with tin snips. Then, I made a mandrel using a 2-1/8" hole saw (usually sold with doorknob mounting kits) and 2 pieces of 3/4" oak. The OD of the cutouts was almost exactly 2". A washer on each side and some nuts to prevent marring the threads, and the whole assembly could be chucked up into my drill press. I sandwiched the rough cut stainless discs in the mandrel, and used a file to "turn" down the plates.
Next, sandwiched the plates one at a time in my downcomer hole drilling jig - drilled a 1/2" hole without warping the plate. I'm using lengths of 1/2"OD tube for the downcomers, with an oversized cap soldered on the end to act as a trap to prevent plate bypass.
As far as the defleg goes, I'll show it when I build it - thinking a 1" inside a 2", using a 2" coupling and a 'fitting' 2" to 1" reducer at the bottom, and a standard cup 2" to 1" reducer at the top. I'm also going to implement a flow-meter (vertical tapered tube type) for repeatability and reporting purposes. Not sure how long I want to make the defleg, but I figure I'd start around 7"

I've got 6 gallons of Hookrum in the secondary fermenter, and molasses enough for 18 more gallons once I get the dunder cycle going.

I'm sure I'll give another update when I finish the build...

[Barney Fife]

Nice work! But that might be too many holes(IE: too much open area) to hold liquid, unless you're really pouring the power to it. Keep us posted as to how well it works or not!

(if it is too much open area, you could solder some of the holes shut)

[coppercreature]

Yeah, that's kinda what I was thinking. Went by the '30%' open area rule of thumb in some other discussions I saw - also, the perforated mesh was dirt cheap, so if I scrap it in favor of bubble plates, I'm not out much. At least I'll have the tooling to whip up some quick bubble plates.
I think I'm going to put one plate just below my sightglass in my VM column, de-tune it by putting in about 3-4 scrubbies, and let 'er rip to see if this plate will hold anything.

[Barney Fife]

I didn't realize the plate was made from a ready-made perforate material; that's way cool, and super-handy! If it proves to be too large an area, you can tin the surface and flow some solder across it to close up some of it, but even simpler still would be to use two of them together, and turn them such that the holes are smaller.

Nice find! Where'd you get the mesh material?

[coppercreature]

Found it here:
http://cgi.ebay.com/Sheet-347-Perforate ... 43a5adbb73

[Barney Fife]

sweet!

[guittarmaster]

My little experiment seemed to suggest that for the sized holes I had drilled, using only 16, 3/32" holes yielded better results over the largest power range. That surface hole area was about 3.5%. Of course this was by using water instead of mash and the plates also had gaps along the sides as they were only cut by hand.

That being said if you could recreate a similar experiment I'ld be very interested in reading the results. I'll probably end up rerunning this experiment outside using some mash this summer when I have a break in my classes. So far my 10 plated column seems to working quite well. If you were to experiment you could use flour paste to seal up some of the holes and use a tooth pick to reopen any accidental plugs. Just make sure you give it time to harden the paste before you add the water onto the plates.

I"m really looking forward to seeing completed!!

GM

[coppercreature]

Quick update: I'm a lazy sod.
OK, so I have the perf column guts put together, with 1/2" downcomers and caps, and I have my 2" column and deflag ready to go, but I still need to surface mount the sight glasses to the column. Just need the time and tooling to put a nice 2-1/8" radius on the unions so I can see what's really going on. But in the meantime, I've put about 25 gallons through my detuned column with a full-perf plate at the top, about 2" under the takeoff, with a sight glass. Yes, the plate holds a lot of condensate and bubbles nicely, but since it's right under the deflag, of course it does. In the detuned column, I put 3 evenly spaced scrubbies under the perf plate, and it did just fine! First batch was a bit light, but subsequent batches recycling dunder gave it a real smooth complexity. I've been happy to leave well enough alone.
BUT, I still have the bug, and I'm still eyeing that 4" stainless dairy surplus on e-bay, and I'm thinking a 4" bubble plate column is my final destination....

-CC

[guittarmaster]

So,

I've been moving forward with the experiments. I have a 40" 2"diameter still with my delph on top. It pretty much is just like my twins but just one piece of 2".

I ran it once near the beginning of summer with four stainless steel scrubbies in it to see what the maximum efficiency would be. That run was 93%. I ran it again tonight but added two more scrubbers and only got 94%- 94.5% pure distillate. I have changed my recipe to a sugar wash similar to one off the parent site, (2cans grape juice concentrate, 1can orange concentrate, 1 Tbls epson salt, 5 gallons water and enough sugar to bring the SG to 10-12 % +1 Tbls distillers yeast: its easy, smells/tastes good, and ferments quickly)

Since my overall set up on this still is similar to 2"flute/ CM-buka-flute-hybrid (what with delph instead of coil and all) I"m going to take the 94% as my maximum efficiency distillate.

I have a 5plate bubble cap tree I will insert and compare to the packing. The plates have 3 caps and a down-commer similar the ones posted elsware on this site. I'll post the link tomorrow if/when I find them. I'm tired, and it's late, and I have to work early tomorrow and post pic of cap if someone is interested this early in the game.

GM

[Usge]

Great research there guitman.

I put my 2" bubbler away for a bit. Found a leak in the top of my dephlegmator (crap@!!). After I ran water through it just a few mins...I could turn it around in my hand and drips of water would come out...so the leak is in the top (crap again). Since I'm going to have to tear it down again to fix it...I think I'm going to go through everything and do some mods.

[Prairiepiss]

I guess I'm not understanding how your getting maximum efficiency numbers on a 40" column with only 5 scrubbies? Or did I read that wrong?

[Usge]

P, I think he was checking the efficiency of the CM from the dephlegmator ....ie. running the column with fewer scrubbies to see what he was getting just from the CM.

[Prairiepiss]

Ok I think I'm following it now. Kinda like finding the baseline of the still?
Thanks Usge.

Carry on sory for the interruption.

[guittarmaster]

Ok I think I'm following it now. Kinda like finding the baseline of the still?
Thanks Usge.

Carry on sory for the interruption.

Yeah, that's it exactly!! Scribbles have the highest HETPs. A 40" booka should have no problem creating 96%, the largest difference here is the the Delph-CM instead of the LM of the booka.

The first time I ran her I had 4scrubbies, the 2nd was with 6. It was packed pretty tightly, maybe I could of gone tighter but it seemed like it could choak. next I'm going to running the bubble caps, then a new perforated, and then the new bubble cap and weir downcommer from te flute mark 2.

Pics and stuff later today.

[guittarmaster]

ok, I've been really busy with classes but since this I had 3 exams this week this weekend is free for me to work on the ol' experiments. Just to show the bubble caps so far I have one finished and four bubble plates without downcommers which i will finish tomorrow. Yeah, they're still dirty but since I'm gonna fire them up tomorrow I'm waiting to clean them.

side ways view.

cap_side.jpg

top-ish

caps.jpg

and her is the finished 2" bubble cap plate.

bubble_cap.jpg

Tomorrow I plan on finishing the downcommers on the 4 remaining plates and hopefully running her this weekend or next. The plates are bolted with stainless nuts and stainless thread- thing. Also note I plan on lowering the top of the downcommer, it's only 98% finished...

The caps are 3/4" with 3/8? raisers x 3 with the 3/8th J-downcommer.

[guittarmaster]

Well, got the caps finished.

plate_tree.jpg

The results were disappointing. I adjusted my delph and power to the setting i always use when running the twins or when i ran with the stainless scrubbies. 10 gallons of 11% mash.

At a little under midnight the base of the column started to heat up, and within 30 minutes the column was in total reflux. I let her go for half an hour and bleed off my forshots. These were at 92%... I was Disappointed it was this low, so after i removed the forshots I put her back into full reflux for another 30 min, so 60 min total reflux with a who 15 min bleed in in-between. This came out at 89% and dropped slowly. It's like I had nothing in there!

I wondered if maybe condensate was dripping around the plates too quickly or something; because i could hear the plates bubbling in there and i could also hear what sounded like liquid down the tree, so i turned the heat up. After increasing power and refluxing for another 30 min I started to take product off again, this time the initial measurement was 92%! "Alright" i thought, "finally got her adjusted." I then went to work cleaning up a little in the basement, looked over and say my alcometer floating WAAY to high! The % had dropped from 92% to 83 in about 15 min, and worst of all i was starting to take the distinct taste of tails!! I had only collected about a quart of what I had thought would be drinkable and BAM, tails.

needless to say so far it was about 3am, I collected about a pint of fores, a pint of heads, about a liter of drinkable 'hearts' and tails starting to come through... on the delph setting that has consistently given me great results in the past, but now was working like a pot still! CRAP... Three more hours of messing with it and i kept getting the same results, It would start in a highish % after refluxing but quickly drop, and the rate seemed to be either on or off. if i increased the power i heard the popping sound of flooding coming from my condenser.

I"m going to run the bubble cap plate tree a few more times before I make an "official" judgement on 2" bubble caps, but i wonder if the size of the caps are restricting the volume of condensate above each cap too much, and is therefor just not allowing or efficient thermal gradient to establish throughout the column.... I might have to try to find some 1.5" sight glasses to figure this riddle out.

However i can say there were pretty obvious transitions into the different stages, fores-heads-hearts-tails. Even with the poor refinement of proof they did a fantastic job and compressing instead of smearing like with a regular pot still head, however it was

GM

[rad14701]

With roughly 1.1 liters of 95% in the boiler at the start I don't think you're way off on your results... Remember there will be quite a bit of total combined liquid on top of those plates which will dilute towards the end of your run... All in all it doesn't sound terrible for a first run... Stick with it and keep us posted...

[Usge]

GM, your results are almost identical to my runs on my 2 incher with 4 plates (1" bubble cap on each plate). I think you should try a run with low-wines (more alc) as Rad suggested. I finally got my new reworked deplegm head done. I'll be posting up pics/specs of it in my old dephlegmator thread. As soon as I can get it cleaned out good...and finish leak testing it...I''m going to resume my experiments as well.