Dual (inner/outer) plated column design

[mymumsaidimcool]

if you are to collect the foreshots seperately and not run them through the system then yeah that'd be greatest.

as you said, valve at the bottom to release them and wallah when you feel like you have enough close em up and letter' run

no smearing
get the foreshots out
no chance of methanol being mixed into the equation.

[zombie]

Thank you. I really appreciate the input, and you all helping sooooo much.

The only similarity between pot stillin' and plated distilling is well uh, they both have the word still in them. So much to learn!

Thx!

[Yummyrum]

Now this an interesting point...Not sure how many plates you are going to fit to your outer column but I would have imagined that the packed column will be Far better at stacking and compressing tje fores and heads...

However...on my VM column I find I have to reduce the power subatantially during this equalibrium stage ( about half an hour and throughout the removal of fores/heads to allow proper fractions to stack and be drawn off slowly to minimize smearing .

.The ability to be able to reduce inner column power will ne interesting....I see you will ne able to reduce the amount of vapour via yoir outer reflux condenser but I am curious how the reboiler will behave with varying amounts of supplied vapour.

You really have a curly beast here :D

[zombie]

Now this an interesting point...Not sure how many plates you are going to fit to your outer column but I would have imagined that the packed column will be Far better at stacking and compressing tje fores and heads...

However...on my VM column I find I have to reduce the power subatantially during this equalibrium stage ( about half an hour and throughout the removal of fores/heads to allow proper fractions to stack and be drawn off slowly to minimize smearing .

.The ability to be able to reduce inner column power will ne interesting....I see you will ne able to reduce the amount of vapour via yoir outer reflux condenser but I am curious how the reboiler will behave with varying amounts of supplied vapour.

You really have a curly beast here :D

I have no idea on the number of plates yet. I am assuming there are proven formulas or dimensions for that. I could also lengthen the outer column downward approx 8", and add some packing there if you feel it would benefit the design. Maybe more of a balance?

The reboiler itself should never really see any vapor from the outer column. That is the main point of it being there. To provide positive pressure from the spent wash at the end of the vapor tube forcing the vapor out of the tube inside the packed section. The secondary function is a way to collect that spent wash, and remove it from the column. BUTTTT

There may be an issue with the re-boiler now that you mention it... If I run a 70-80%ABV pre charge that would boil off at a faster rate than the main boilers 12-15%ABV. Maybe pre charging with the same wash as the boiler would be better, as what will wind up in the reboiler will be leftovers anyway (spent wash).
That would keep the Temps. the same in both boilers, and powering back to slowly run fores would be equal, if not slightly lower temp. due to less ABV after stabilization in the reboiler.
The only potential issue there is a longer collection period for heads. Maybe? Maybe not? Couldn't make that much of a difference in what is really a 2.5 inch column.

I think the way to run it would be drop power, stacking in full reflux, pull fores from each column simultaneously, slowly drop reflux from the outer allowing vapor to enter the inner, then slowly drop reflux on the inner to pull product. I don't think this could be run without windows because there would be no way to detect over running the inner, or losing stacking on the outer.

You are right!!! It is a Curly Beast. I can't get this whole thing out of my head! You know how someone asks... Who was that guy in that movie, and it's right on the tip of your tongue but you can't say the name for the life of you? Same feeling.

[zombie]

I ave another question that came to mind. While I am cutting metal I thought of adding an 8" section of packing inside the boiler but above the wash level to the 8" outer column.
Does anyone feel there would be any benefit to this addition? Mainly is 8" of packing enough to actually do anything?
I am also thinking of the total surface area of the packing as well as the depth. I don't want to clutter things up if there would be little or no gain from it.
Essentially 8" of 2.5" packed column added.

Thanks guys.

[zombie]

I've been looking up plate designs, and had a little success. Little is the key word. What I have found as a genereal rule is 1.5-1.6mm thickness for the plates, and 1.6mm hole size. Spacing seems to be harder to nail down.

I have several suppliers for metal, and one suggested I start with perforated plate. I think it would be easier to fill excess holes (if needed) rather than drilling several thousand holes in stainless.
My thought process is Tig welding the stainless plates into the outer 8" column, and sliding the inner 3" column inside that. Obviously this can/should only be done once so I would like to get it right the first time.

Are there any opinions on this material... http://www.onlinemetals.com/merchant.cf ... &top_cat=1
I am considering this material for the outer columns plates.

I will be using copper plates for the inner column, and will have to fabricate them by hand. Any links to a proven plate would be GREATLY appreciated. I have seen all sorts of patterns, and thoughts on why they work best but I hope you all have a consensus on what really does work.
There will also be adjustable down comers on all of the plates. Stainless threaded rod (drilled centers) for the outer plates, and hand made threads on copper pipe for the inner column. I decided this due to the MANY differing opinions on down comer height, and varied results in purity/flavor carry over.
Also I determined the plates should be installed at 90* to the pipe/column. The original design had the plates at a 3-5* angle mounted in a see saw fashion. The designer explained that was to achieve reflux within the column.
That will not be needed as I am installing reflux condensers on the tops. As for my prior post asking about an extra 8" of packing on the outer column... I cut the extra pipe, and will make that a module that can be added/ taken out as seen fit.
Almost forgot... 8 plates per column spaced at 4" apart. Sound reasonable?

The pile of cut up bits is growing... Thanks guys!

I appreciate any thoughts or input

[Yummyrum]

1.5mm holes on a 5mm grid seems to be the accepted figure around here.

With a slide in tube in the centre , the plates are going to have to be machined very well .8 plates with a holw in tjem to slide a tube through.....definitely not job for hand tools 8-}

You will need a very clos fit so you don' t get bypassing....

Wondering what plate arrangement you will have with the down commers...will it be an alterating concentric thing or just like standard plate ,just with a big obstruction in the middle of it

[zombie]

Thanks,
I have been looking thru the "library" section, and found Picts of industrial Perf plates. 12' across but just large scale versions of the material I linked. I understand plate thickness x hole size is the critical measurement to get a balance able plate.

Using 1.5mm holes at 5mm spacing I assume is on a 1.5 or 1.6mm thick plate stock? I want to keep as much of the build based on proven designs as I can.
I am thinking 4 down comers per plate. Offset from the plate above, and below I think I will have to scale these down to prevent blow by. Is that correct? Maybe 4 x 1/4" or perhaps 1/8"? Or perhaps caps on all of the down comer bottoms?
I am beginning to think a water jet may be best for cutting all these plates so I will have to have these dimensions/ideas sorted out. So yes you are correct... No tin snips here.

I realize the close tolerances I have to achieve. That is most of the attraction of this build or me. There will have to be weirs built on the inside cut of the plates but not for liquid retention. My intent is to make them so tight they will NOT fit over the 3" inner column. I know???????? I can freeze the inner column, and heat the outer column, plates and all. The expanded column/plates will slide right over the frozen/shrunken inner column. I do this all the time with bearings, and cylinder sleeves. I can refreeze the inner column with nitrogen to pull it out to clean or adjust down comer height.
The inner column plates, and vapor feed tube are addressed in a similar manor yet slightly different order.

That's the plan for now... I just need numbers to make it work. Scaling down the big industrial columns appears to be where all this fractional "hobby" distilling began. It's just hard for me to read thru all the Tech mumbo jumbo to find one paragraph that I can understand. Plate design is sooooo full of mumbo jumbo but no single reference to hole placement/plate thickness/hole diameter. I assume this is because of all the different operating parameters of different columns, and environmental factors that a base line formula is subjective?

Thanks for the help sir! It is keeping me moving in the right direction

[Frothwizard]

Don't forget to take pictures of all your components and there definitely has to be a video of you freezing a column with liquid nitrogen while you slip another column over the top...

[Yummyrum]

Zombie
Surely you have had a look at the plated column section on this forum.Although every one is slightly different , they are all based on the same formula....Its not to hard to figure it out........and all the stills built work .

Its all tjere...plate spacing...downcomer diameters and hieght ....plate holes and grid.Plate thickness..

They really seem to be a very tolerant beast...I don't recall anyone building one that they wern't happy with

[zombie]

Don't forget to take pictures of all your components and there definitely has to be a video of you freezing a column with liquid nitrogen while you slip another column over the top...

You are right about that... It does deserve a video. For the initial freezing I hope the bait freezer will be enough. Nitrogen is just for dis assembly down the road to isolate on component.
Once I have all the bits needed per section I will of course document it all as it is built. Three main sections, and three main builds.
It won't go quickly but I promise I will post as I build. It is the least I can do to repay all the advice I have received.

[zombie]

Zombie
Surely you have had a look at the plated column section on this forum.Although every one is slightly different , they are all based on the same formula....Its not to hard to figure it out........and all the stills built work .

Its all tjere...plate spacing...downcomer diameters and hieght ....plate holes and grid.Plate thickness..

They really seem to be a very tolerant beast...I don't recall anyone building one that they wern't happy with

Yes I did. I do seem to find lots of partial info that I have to piece together too. Some of it later proved out to not be as good as first thought. For instance MacStill posted in a thread how he is done trying Perf. Plates in stills. Doc, and several others have pointed out how slight modifications make huge differences ect...
I'm just attempting to round up all the best design info in one build
.I think what makes all of the builds at least work are a few constants in "hobby" still parameters. For instance... Vapor speed. All the stills built here are relatively similar in power, and column size/volume. Plate spacing seems to be largely based on Modular parts available. Of course all the mashes/washes have similar Alch./water content, and specific gravities.
All these variables are so close to each other that failure is almost not realistic. I get that part.

I think what may be missing from how you fellas may perceive my incessant questions is the fact that I never heard of fractional distilling until I decided to distill neutral type spirits, and presented MY version of what I thought might work. Of course I read all the wrong info, and watched all the wrong videos.
Now I have jumped into the DEEP end of the pool, and want to learn everything about the formulas that make industrial / advanced hobby distillation work.

To this point I have learned soooo much it is makes Me laugh at what I thought just a few months ago.
I found some good info on industrial plates that explain how/why they work as well as potential problems with each type. That is what led me to the Perf. Plate I linked, and my questions about hole spacing, and diameter.
Apparently (not thru reading it all yet) too many/too large, combined with too slow vapor speed does not allow the plates to hold liquid. Plate thickness has a direct relationship here.
Plate spacing affects speed, and density also (I think).


I realize many of you here could easily get a degree from what you learned and I want to join that group. I don't want to just make hootch.
Rather than copy a design I want to design a still and know exactly what is happening the entire way. That is the fun part for me. Building is just proving my idea, and making hootch is just a by product. I have a pot still for hootch. Now I want a one of a kind still for really great Vodka/Gin.

To cut a long post shorter. I will focus on adapting proven designs. No need to re-invent everything. I keep forgetting that part.

Thanks again. Please keep any thoughts coming because every post has helped me realize how much more there is to know. Thank you all for helping.

[zombie]

Hey!
I found something that relates to my question about placing 2-4 down comers spaced around the plates. Here is a quote, and a link to the article... http://www.freepatentsonline.com/6715741.html

"The efficiency of multiple down comer fractional distillation trays is improved by distributing the liquid egressing from the bottom of the downcomers in a manner which provides a uniform length liquid flow path on the next lower tray. This is accomplished by liquid distribution devices suspended below the downcomers of the upper tray, with the devices running parallel to the downcomers of the next lower tray and being adapted to collect the falling liquid and then disperse it onto the decking below along the length of the lower downcomers through openings in the distribution device."

In a nutshell it explains how setting a flow pattern can improve efficiency.
However it was just explained to me here (Down comer height thread) that these smaller columns have such a violent nature that flow patterns are not really a concern.
Sooo... I can't help but believe that every little bit of efficiency adds up. In taking the circumference of the outer column into account I do feel it best to install four down comers per plate offsetting them from the plates above, and below. At the base of each down comer I can install a "shower head" type cap (holes drilled in the sides) to disperse the liquid out across the lower plate This set up should allow the plates to work more uniformly (no deep or cooler zones), and lesson the chance of flooding (easy egress to the down comer). Flooding is a very real concern because I will have to control the output from the outer column by way of reflux vs heat to avoid flooding/over running the inner column.
Which brings up my next realization...
Another DUH moment. I have continued to state the outer 8" column is in essence a 2.5" column due to the 2.5" remaining all around the inner 3" column. WRONG!!!
I realized this when I mocked up the two pieces today. I can fit seven 2.5" columns inside the outer shell with the inner column in place. That does not count the free space around each. Now since I am not the brightest bulb in the house I am not sure what this means or how to determine what I DO have. What I THINK it translates to is a 2.5" column (vapor speed potential) with roughly 7 times the surface area per plate (vapor interaction potential). Can anyone translate this for me.? Or do any of you smarter fellas know what formula or equation I would use to figure this out?
As this progresses I m more, and more certain it will work brilliantly. Just a shame I'm not quite smart enough to know why!

Thanks!

Ps. There will be 2) 5kw heating elements running this so I believe there will be more than enough power, and all of the vapor from the outer will be forced into a 1/2" injector pipe (thus the reflux condenser on the outer column to control the potential surplus of positive pressure, and the concern for tray flooding).

[zombie]

Found some interesting numbers on the columns using this site... http://www.handymath.com/cgi-bin/cylind ... bmit=Entry

Basing it on a 36" x 8" outer, and 60" x 3" inner column I come up with roughly 22.6 liters total capacity. This includes deducting the volume of the inner column inside the outer.
In translation this equals a 4" column at 9' tall. Figuring one plate at every 6" of a 9' column that makes 18 plates. Pretty much on par with the 16 plates I estimated for mine. Plus I have a 20" packed section within the boiler.
While I am not declaring a victory as to the design it appears I will be on goal for a single run azeotrope.

another DUH! Take the 3" column space out of the 8", and get 5. That's the working size...Duh!

Thanks for bearing with me.

[Bootross]

another DUH! Take the 3" column space out of the 8", and get 5. That's the working size...Duh!

I don't think that's quite right zombie, the vapour speed is based on the cross section area:
Area of a circle = pi x (radius squared)
Area of an 8" column = 50.25 square inches
Area of a 3" column = 7.07sq in
Therefore an 8" with a 3" up the middle will have 43.18sq in remaining (50.25 - 7.07)
Which is equivalent to a 7.4" diameter column.
:-B

What this means for your design, I'm not sure :think: but those are the numbers.

[zombie]

another DUH! Take the 3" column space out of the 8", and get 5. That's the working size...Duh!

I don't think that's quite right zombie, the vapour speed is based on the cross section area:
Area of a circle = pi x (radius squared)
Area of an 8" column = 50.25 square inches
Area of a 3" column = 7.07sq in
Therefore an 8" with a 3" up the middle will have 43.18sq in remaining (50.25 - 7.07)
Which is equivalent to a 7.4" diameter column.
:-B

What this means for your design, I'm not sure :think: but those are the numbers.

I'm not sure what it will mean either. I have much more to learn.
Thank you so very much for figuring that out for me. At least now I have solid numbers, and know how to attain them.
That is why I decided to post all of this. I could never design something like this alone. Or even with the help of 20 of my closest friends. They all drink a bit, and I have other aaaaa hobbies. The lights glow dim in Da South.
Thanks!

[Yummyrum]

Zombie not sure if you have read this...its about vapour speed/column Dia Here

This was always my concern with this build , balance between the two diameters surface area.

[zombie]

More numbers... (everything is approx. for ease of translation)
The main boiler is capable of 10 kw. Lets say 7.5 kw is running rate

7" outer column (by area) @ 7.5 kw= 23cm per second vapor speed
2.8" inner @ 7.5 kw= 139cm per

I do have to nail the math down but these are just rough numbers. Because of these I just avoided a potentially fatal design flaw. The plates have to be designed for the vapor speed they are to be utilized with.
Reflux/shotgun condensers will only control vapor speed exiting the column but NOT within the column.

That is why all the stills you fellas build work. They are all based on the same/similar parameters. This dual column actually has two different operating parameters within itself, and I almost muffed it all up.

The larger column is running at the low end of acceptable vapor speed while the inner is operating at the high end of acceptable. Reflux will only allow me to balance the two but not alter either.

My new quest? Plate design... First thought says more/larger holes for the inner, and less/smaller for the outer. Perhaps packed for one, and plated for the other? Maybe Bubble caps for one? Both? Man this is tough! But fun for sure...
I hope you all don't mind my posting all this. Thinking out loud as it were.

[zombie]

Zombie not sure if you have read this...its about vapour speed/column Dia Here

This was always my concern with this build , balance between the two diameters surface area.

That's crazy cool you posted that. I was off reading that, and thermal conductivity pages to to figure a way to balance the boiler/reboiler to adjust the vapor speed results.
That got WAY over my pay grade so I went, and am going more into plate design to adapt to those numbers.

I could change the numbers by changing pipe size... say a 4" in the center. That may be the ticket. I can save my three inch for something else. It gets the numbers closer, and will allow some latitude on boiler power.
Glad you are following this. Thanks.

One of the members on MD has poked at me about the "lights coming on" moments. Lately it's been Dynamite moments. getting blown away here.

[Yummyrum]

Bubble caps might be your answer as the plate is not reliant on vapour power to keep them loaded like a perf plate .

Here's another gem from the Aud Library