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adamOVD

Running Two Columns off a single pot

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3 minutes ago, FijiSpirits said:

 

 

@southernhighlander. Funny you mentioned the lower reflux setting on #1,  I was thinking it would want to be set to ~180-190 ish just to push stuff thru the bottoms on #2.  But then you lose a lot of rectification available from #1.   Tough balancing act it seems.

 

 

 

 

It's easy to balance 3 columns with 1 thermostatic valve and 2 pumps.  Your thumpers would be a huge hassle.  Pumping the column condensate works much better.

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1 minute ago, Southernhighlander said:

It's easy to balance 3 columns with 1 thermostatic valve and 2 pumps.  Your thumpers would be a huge hassle.  Pumping the column condensate works much better.

The pricing on peristaltic pumps makes one want to do about anything else... ;)

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Concerning speed.  I have a little 2" column still in my test lab that processes 30 liters of corn mash per hr.  Our bigger column still designs are some of the most efficient and fastest in the industry.

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10 minutes ago, FijiSpirits said:

,The pricing on peristaltic pumps makes one want to do about anything else... ;)

Why would I use a peristaltic pump?  When you pencil out the alternatives, my option makes far more monetary business sense than any other option currently available.   As long as people want to put 1,000 gallon vodka stills in 14' spaces, my stills will keep on selling.  Pump kits are a very small percentage of the cost for our Pro Series and Signature Series stills. 

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What sort of pump would you recommend?

 I guess I always just got stuck on the “meterable and adjustable flow” features for the peristaltic as well as the natural antibackflow and self priming aspects of it that I never really considered another option.

 

One of those little air diaphragm pumps everyone uses for moving high proof, used with a decent regulator might be just fine i guess.

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We use an air pump with regulator and they work great for pumping column condensate.

 We use peristaltic pumps for our continuous column stills for pumping mash.  

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I run a two column (1st column is 4-plate, 2nd column is 12-plate, both columns have a defleg).  We have trouble hitting 190 proof consistently and are manipulating the flow to the 4-plate column defleg.  I read in this thread a theoretical temp of 180-190 to (presumably) allow lots of ethanol through to the 12-plate column and only knock down the water in column #1.  Our 2 columns have a drain back to the pot.

I am wondering whether the job of the 1st column is to do lots of work (set at 175-180) and allow column #2 to polish to the vodka or set at 180+ to leave most of the work to the 2nd column. 

I haven't been able from this thread to understand the role of the two columns (a previous thread suggested to have virtually no cooling in the 1st column).

If anyone can point me in the right direction it would be greatly appreciated.

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The role of the first column is to do some dirty work in front of your rectifier. The issue is that too much good alchohol gets sent back to the kettle. Kind of like swimming against the tide or driving with the windows down while your A/C is on.

How much ceiling height do you have remaining? Are you able to add plates to the rectifier? If so, you'd be better off bypassing column #1 altogether and send vapor straight to column #2.

The strategy of  little to no reflux on column #1 is to reduce as much as possible anything returning to the kettle as bottoms from column #1. 

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bcoutts,

 

I can sell you a simple pump kit that will allow you to pump the condensate from the bottom of column 2 to the top of column 1 (the 4plate).  As the columns are currently set up the addition of the pump will give you the equivalent functionality/efficiency of 2 more plates because with the pump the 2 columns combined are functioning just like a single vertical column.  Currently you are running with the equivalent functionality of 14 plates.  If you add the pump and no plates then you have the full functionality of all 16 plates.  If you add 2 to 4 plates to the 4 plate column along with the pump your still will be no taller than it is now but you would have the full functionality of all 18 to 20 plates.  20 Plates will give you the highest proof in the shortest amount of time.

We can fit our vodka stills in spaces with vertical height limitations of as little as 10'.  Very few others can offer that.  Give me a call at 417-778-6100 or email paul@distillery-equipment.com

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22 hours ago, smaug said:

 

The strategy of  little to no reflux on column #1 is to reduce as much as possible anything returning to the kettle as bottoms from column #1. 

I don’t understand the bit about returning column bottoms to the boiler. Why not pump them back to the top of column 1. That’s what plenty of big operator old school continuous rig have done for decades. 

 

Honestly maybe it better to just have a separate simple stripping column setup and a second. finishing setup. Hell I don’t know.   I’m confused. 

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It's best to do a stripping run, then the spirit run in a 20 plate for vodka.  I would run 25% to 35% low wines for vodka. The stripping still should be sized to 3 times the capacity of the spirit still, if 25% low wines are to be produced.  Our pro series stripping pot stills will do a stripping run in as little as 2 hrs after the operating temp is reached.

  Our new continuous column stills will be the best option for stripping.  We will have them available in sizes from 2" to 36" in diameter soon.

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Well at least I understand why you lose so much efficiency running two connected columns next each other. It's pretty simple when you think about it. The lighter fractions can move up, but the heavier fractions cant move down, because they are isolated from the pot. Pumping hot high proof condensate from column 2 back to column 1 at a steady rate so it doesn't wreck the equilibrium of the first column seams like a challenge though.

Super interesting stuff, but doesn't help me run my dinky column any faster. I was making things other than vodka, and was a bit behind in production, so I've just been running the still as is. But I'm mostly caught up now, and I'm gonna start tweaking things, one at a time. Starting with moving the plates to the bottom. I'll report back after I've played with a few things if anyone is interested.

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On 9/14/2019 at 6:48 PM, adamOVD said:

Pumping hot high proof condensate from column 2 back to column 1 at a steady rate so it doesn't wreck the equilibrium of the first column seams like a challenge though.

 

It's no challenge at all for our customers.  We have lots of them out there with multiple columns, running our pump systems with no issues.

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I don't know if anyone cares, but I've been climbing up and down a ladder rebuilding my column and these are my observations. First I put the plates on the bottom. The plates stacked beautifully. When I run them on top they run a little dry. However I couldn't get the distillate to come off over 190. This was at the beginning of the run where 190 is pretty easy at my previous configuration. 189.6 was the best I could do using every trick I know. I really wanted this to work. I tried loosening up the packing as well with similar effect. I could hit 190, but not any higher. It's just such a huge jump from 189 to over 190, that I think running low and slow is my only option. If I decide to try SPP, which seems to be my only other option with this column, I'll check back in, or if I get my original double column idea up and running. Or maybe I'l run the numbers and l be able to justify buying a 6" column. Thanks for all the input though, and the education on running sequential columns.  

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I’m definitely interested.  Other peoples issues are great ways to learn!!

 

Basically the trade off will be more speed fro less purity.  If you can live with the slightly lower purity you should gain speed.

 

There is no arguing that more packing provides more rectification.  But that rectification comes at the cost of speed in the same column size.

 

Have you looked at Still dragons Procaps?  They are very efficient and very fast.  I think you’d need about 16 tho.  I run perf plates and procaps and the procaps are my preference for their larger operating range while still have speed.

 

I’ve been spending more time working on my ferments to clean them up and maximize what I can do with them.  Then on my stripping runs I will water the spirit down to less than 30% with clean filtered water.  These three are critical things if you aren’t doing them, and they can make far more difference together than an extra 2-3% ABV on the strip (especially the ferment).

 

I could take off 95-96% on my 11 plate if I really wanted but the flow rate would drive me batty and when I have done it, the difference in taste is so minimal that its not even worth it.  I’m certain others have had different experiences.  My sugar washes used to be all over the place so I’m not a good metric

 

take that for what it’s worth, there are others with far more experience than I that’ll chime in.

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I'd be fine with a slight drop in proof. I've got a "full flavored" vodka. I'm in the US though and my efforts are mostly to conform to the standards of the TTB. 

I do have a 7 plate 6" column though, and now I'm thinking of trying to make that work alongside a 6" packed column. 

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Adam,

 

You can increase your proof and decrease your run times by adding a couple of lbs of salt to your mash.  The salt will help to break the azeotrope.  Put it in your mash after fermentation, once the mash is in the pot.  The salt has absolutely no effect on the flavor of the distillate.  Use sodium without iodine.

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