When to draw the line?

eviljesus · Post by **eviljesus** » Sat Jun 30, 2012 6:12 am

Hey guys,

Been looking everywhere for this but cant find it anywhere.

Ive got a 2" 1.2m long Boka which has been going quite well for a while but I've happened across another 1.5m of 2" copper.

I'm thinking about joining these together and making a larger column for use on my big boiler (200 litres) so i can do large runs all at once.
I do have balcony I can access the business end from so no dramas there.

Question is - is there a point at where it just isn't worth the extra height? I do pretty well, and spirit is quite drinkable the first run but the second spirit run does make a difference. Would a 2m+ high column get it to the point where one run is enough (all things being equal) and what problems are likely to be experienced trying to pull this sort of caper off?

No interest in doing another still head either, I only run neutrals, so a new different type of head would be wasted on me. I'm only considering this because I got the gear here to join it all together without any mucking around and this design has worked great for me.

Cheers,
Evil.

Post by **mash rookie** » Sat Jun 30, 2012 7:19 am

Without doing the research for you or giving you an easy answer I can tell you that the information is on the parent site.
There is a maximum diameter / height ratio of diminished returns on increased height. The parent site is a great resource. Please use it.
Not trying to be onnery, just reminding folks how much info is there.

Mash Rookie

eviljesus · Post by **eviljesus** » Sat Jun 30, 2012 7:40 am

I've read and re-read the parent site to the point now where I'm no longer recognizing what I am reading and am perhaps just confusing, more than helping myself?

According to here: http://homedistiller.org/theory/refluxdesign/height" onclick="window.open(this.href);return false;" rel="nofollow
Question
It looks like I am pretty much at the limit of what its going to do for me (I'm using scrubbers btw) I understand that the ABV probably wont go up much (if at all, im already hitting ~94%) as I'm pretty much at the limit and I am not concerned here. Does this mean that people with longer columns (>1.5m) are wasting their time?

EDIT: FOUND THIS! I knew I had read it somewhere.
FROM: http://homedistiller.org/equip/concept" onclick="window.open(this.href);return false;" rel="nofollow
Packed Reflux Column
As a general rule of thumb this should be 30-55mm diameter, and 600-1000 mm tall (14-20 times the diameter). (see Reflux Still Design Calculations to accurately work this out for your requirements). If too narrow, the liquid trying to drain back into the still will be blown out the condensor by the vapour; if too wide it will cool too much (no vapour get out - all condenses prematurely), or there will be inadaquate contact between the liquid & vapour and not much purifying will happen. If in doubt, go slightly too large, then shove a stainless steel rod or two up through the packing to take up some of the space. Packing best to use is stainless steel wool / turnings. Pack as much in as possible, but loose enough that you can still easily breath through the tube if you try. Position the pre-condensor ABOVE the packing, so that the liquid it condenses falls back through the packing. Some designs (eg Partyman's & StillMakers) have the condensor below the packing. Although these columns will still work, the only purification taking place is via vapour/liquid that has cooled inside the packing - quite a lesser amount. The greater the reflux ratio through the packing (the ratio of falling liquid to rising vapour), the cleaner & stronger your alcohol will be.

If anyone still has control of the main site, maybe this should go into the column height reflux theory page?
Question above still stands.
Is anything over 1.5m of packed column a waste of time and an excercise in futility? What is the point of diminishing returns?

Post by **rad14701** » Sat Jun 30, 2012 6:43 pm

Newer specifications are 12x - 24x column diameter with diminished returns in the 30x range... Many here have had success with 48" of packed column using 2" copper... That gives a total column height of ~60"... But shorter columns have also proven successful... Experimentation is part of what keeps this hobby addictive...

eviljesus · Post by **eviljesus** » Sat Jun 30, 2012 7:41 pm

Thanks Rad. Looks like I'm already sitting up the higher end of the scale.

With a longer/higher column, do you need more heat to push it up higher or that doesnt matter?

Post by **rad14701** » Sun Jul 01, 2012 5:55 am

As you go taller the potential need for column insulation increases... More heat may also be required but then there is the added potential for flooding... It becomes a balancing act which is why we refer to diminished returns... You can only get so pure but if you need to slow down the output rate then reducing the packed column section height should be considered... One thing I've thought about is a modular column with several varying length sections which would allow mixing and matching to optimize performance... Food for thought... However, that does increase build complexity and expense...

eviljesus · Post by **eviljesus** » Mon Jul 02, 2012 10:27 pm

Thanks for that info rad.

I have some insulation that I can add to the column to keep it fairly even and prevent heat losses.

I'll keep everyone informed of how I go.

Cheers,
Evil.

jimmyjames1981 · Post by **jimmyjames1981** » Tue Jul 03, 2012 8:04 am

It seems that alot of these threads having been popping up lately about making 2" columns taller to increase output and purity, if your looking to increase output and maintain purity your going to have to increase column diameter, sure there are ways to slightly increase your output on the 2" but the increase would be miniscule, where would you put a 9' tall column plus boiler height??

Post by **Oxbo Rene** » Tue Jul 03, 2012 8:14 am

Last year when I did my spirit run I had 48"s of packing = I drew off my product at a steady 94%.
(2nd run, low wines @ 40%) = 6 gal ......
This year, I decided I could double the thickness of my scrubbies (copper), which I did,
also took off the top (junction where I connect column to LM/VM section) and could add
another 6"s of scrubbies in there = made my spirit run the other day = I drew off my product at a steady 95%.
So, that's about all I'm going to strive for = can't really argue with that ...........................
And yep = two-three drops a second = a long day ! ! ! .......................

eviljesus · Post by **eviljesus** » Tue Aug 14, 2012 10:03 pm

Guys,

Just as an update, I am going with a modular column. Hence my other thread :S put on the flanges - success and clean it up - failed.

Jimmy, I can put it downstairs out near my patio, where I can adjust the workings from upstairs.

100L boiler is on the way. This is still a very decently sized run and will be alot more user friendly than setting up my current setup.

Cheers

RevSpaminator · Post by **RevSpaminator** » Wed Aug 15, 2012 7:46 am

jimmyjames1981 wrote:It seems that alot of these threads having been popping up lately about making 2" columns taller to increase output and purity, if your looking to increase output and maintain purity your going to have to increase column diameter, sure there are ways to slightly increase your output on the 2" but the increase would be miniscule, where would you put a 9' tall column plus boiler height??

Do we need to add falling to the list of safety precautions?

eviljesus · Post by **eviljesus** » Wed Aug 15, 2012 3:04 pm

RevSpaminator wrote:Do we need to add falling to the list of safety precautions?

That may be a distinct possibility

Post by **LWTCS** » Wed Aug 15, 2012 3:16 pm

Adding a bubble ball styled micro thumper To the base of your column has proven To nearly double
Collection speed with little To no sacrifice in purity.

eviljesus · Post by **eviljesus** » Wed Aug 15, 2012 10:52 pm

LWTCS wrote:Adding a bubble ball styled micro thumper To the base of your column has proven To nearly double
Collection speed with little To no sacrifice in purity.

This has me VERY interested. I have been reading over your thread L this morning actually and it has me interested. I didnt know it applied to a boka though, I should of been paying attention.

This has changed everything. Back to the drawing board....

Post by **LWTCS** » Thu Aug 16, 2012 3:15 am

Most of the info about this type of set up where a miro thumper sits below the packed column is on a thread called bubble ball ( or tbe like). And is located over yonder cross the road.
Improvements have been noted by many users by this point.

eviljesus · Post by **eviljesus** » Thu Aug 16, 2012 3:18 am

Found a thread on the thumpers... very interesting. If anyone else is keen for a read check out LWTCS previous efforts http://homedistiller.org/forum/viewtopi ... 16&t=11436

EDIT:
Also alot of pertinent information in here:
http://homedistiller.org/forum/viewtopi ... l#p7001353

eviljesus · Post by **eviljesus** » Tue Aug 21, 2012 4:52 pm

Inline thumper 2" torpedo/bubble ball ordered and on the way!

For attachment onto the bottom side of a 2" boka column.
I will keep everyone informed on progress.

whiskeytripping · Post by **whiskeytripping** » Tue Aug 21, 2012 5:10 pm

Eviljesus, where did you find a bubble ball for sale?, I looked for a little bit one day and couldn't find any for sale, they were discontinued at the place I did find

eviljesus · Post by **eviljesus** » Thu Aug 30, 2012 5:00 am

Hey guys,

While my still is all apart for, I decided I might as well do a full rebuild, trying making it a much more effective beast. It is a 2" Boka with 75cm of SS scrubber packed column. I have no problems pulling off 93% for most of a stripping run.

I've been reading through this thread: viewtopic.php?f=17&t=30430 on improvements to LM columns. Reading (and taking) on myles' post on page 1.

(Taken from thread)
1. Increase the column length to at least dia x 20.
2. Insulate the column and the boiler.
3. Use RLM instead of LM
4. Use of centering collars in the packing
5. Increase the diameter of the reflux return line to cope with higher volume of reflux due to higher boiler power.

Here is the current design that I am working with here.

I am working on implementing his changes but have a few questions in particular with regarding to #3. I understand the concept but I have a question on whether or not I should be feeding it into the top of the packing, the bottom of the packing or back into the torpedo/bubble ball for best effect on this particular still. Which of the proposed red or green reflux return lines would you use? If you used the green return and fed it back to the bottom of the column/ball, would you put a valve to control the amount at the bottom as well?

Also, is there a reason people are inverting their caps on the bubble plates? What effect does this have? I can find where people have done it, but for why?
There is also alot of info on the centering rings which are obvious in their function. From my reading, these should be distributed more towards the bottom of the column. I am planning on 3 rings, 2 in the lower 2 thirds and one in the upper third of the packing, has anyone attempted this? What are people using as centering rings?

Appreciate the help guys.

Cheers,
Evil.

Post by **rad14701** » Thu Aug 30, 2012 5:32 am

My preference is to have the reflux return at the top of the packing and only have one valve for RLM operation...

If you return the reflux to the bottom of the column then close to pure ethanol is having to fight its way all the way back up through the less pure mixture in the structured packing, potentially getting dirtier along the way... The fact that the reflux was condensed from distillate vapor that had already been cleaned up as it rose through the gradient within the equalized column leads me to believe that for efficiency the reflux should be reboiled closer to the top of the column... The flip side to all of this is that by returning the reflux lower in the column you are attempting to artificially stretch the HETP's to a taller height than they would naturally attain...

If you really want to venture where few have gone before just build it with both returns and experiment to see which works better... Just as with plated columns with plate drains this might be a way to experiment... I've always wondered what three or four selectively alternate reflux return points might prove out from a performance and purity standpoint... But if I was to have just one return point it would be at the top rather than at the bottom...

That's my two cents...

Post by **mash rookie** » Thu Aug 30, 2012 6:03 am

His is a valuable two cents.

I would only return liquid half way down at most for the reasons Rad mentioned. Its called “Entrainment” and refers to the contamination of vapor by less distilled vapor. That being said, I designed and built a reflux return line on my flute that helped considerably on separation of fractions. Its my opinion they will be less affective on a packed column but that has not been proven. A reflux return drain will slow production.

You might read Myles thread on reflux splitting if you want to burn a few brain cells.

With recent testing that I have done I would say that insulation is more critical than your centering rings at reducing wall affects. Do use rings but be careful they are not restrictive to vapor flow.

HETP “Height equivalent to theoretical plates” Or greater distillation cycles in a given distance.

eviljesus · Post by **eviljesus** » Sun Sep 02, 2012 4:31 pm

Thanks for the posts guys. I'm looking over it all today and will post back with any info that I find.

If anyone else is interested the thread can be found here: http://homedistiller.org/forum/viewtopi ... =1&t=29992

Thanks for the point in the right direction.

eviljesus · Post by **eviljesus** » Tue Sep 25, 2012 9:56 pm

Well guys...

Look what turned up today...

Post by **myles** » Wed Sep 26, 2012 3:42 am

I am going to jump in here and say that the reflux splitting is only going to be of any benefit in a tall column. By that I mean >30x diameter. Further it will most likely only be significant in the later stages of the run. Probably only of interest to a small group of folks aiming for maximum performance of small diameter columns.

I have come to the conclusion that there are two ways to get maximum product rate.

1. You can run a tall column tuned to the max with reflux centring, wash ph preparation, packing density tweaks, choice of packing material etc etc
2. You can run a wider column (shorter than theoretical optimum) but run it more slowly with a higher reflux ratio to depress the HETP.

By using method 2, the increased throughput of the wider column compensates for the reduced vapour speed, so you still get a faster product rate.

I predict in the future we will see more short wide columns mounted over bubble balls, and they will probably be packed with SPP.

It is sort of like comparing a hot hatchback to a muscle car, both can get to the same speed, but 1 bouncing off the rev limiter and the other is just cruising.

eviljesus · Post by **eviljesus** » Wed Sep 26, 2012 5:24 am

Thanks for your input myles.

My goal is not to get maximum rate, although I am after something decent, but more to make sure the column is working at its utmost to get the best spirit I can from it. If I get a decent flow rate at the same time I will be even happier.

Post by **myles** » Wed Sep 26, 2012 11:41 am

That's OK. A lot depends on the type of packing used, although I think I would use reflux re-distributors anyhow to prevent column wall channelling.

One at the top of the column. Serves two purposes centres the reflux, and also increases vapour turbulence going into the reflux condenser to increase condenser efficiency.

One at the column mid point, and another mid way between there and the foot of the column.

Summarised from what I have read about column tuning:

1. Use a packed height of 20x diameter.
2. Insulate the boiler and the column.
3. Switch to RLM instead of LM.
4. Use centring collars (or re-distributor plates).
5. Increase the diameter of the reflux return lines to cope with the larger flow caused by higher power use.

Note: Some of the folks pushing the boundaries, have been putting an empty column section between the top of the packing and the take off point. This is a buffer zone to cope with liquid reflux being ejected out of the top of the packing by the increased vapour speed.

whiskeytripping · Post by **whiskeytripping** » Wed Sep 26, 2012 5:40 pm

Eviljesus that's a fine looking little torpedo you have there, has it really sped up the whole process of your runs? I'm running a 2" potstill and interested how much time that little bolt on device can speed things up and if its worth it.

eviljesus · Post by **eviljesus** » Wed Sep 26, 2012 11:34 pm

Honestly mate, not sure how it goes yet. I havent fired her up to run. Gotta wait till I get the ferrules and boiler on the go... roughly 2 weeks until first fire up.

Myles - I'll have a look over that info, process it and get back to you.

What are you guys using as reflux redistributors or or centering rings?

Post by **myles** » Thu Sep 27, 2012 12:25 am

I think the centring rings work fine on a 2" column, just don't make the central hole too small.

I used a 1.4" hole in my 2" column and it seems to work OK. The multi hole re-distributor plates though will probably be more efficient on a larger diameter column, as they will spread the condensate more evenly over the packing surface.

One thing that has been reported though, if you use higher vapour speeds, is that you need to leave a void in the packing above each ring or plate.

Home Distiller

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