Double Column stills

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Madshine
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Double Column stills

Post by Madshine »

I've seen the Still Dragon Double Dragon stills around. They've got 2 columns running off of one boiler. Saw ond first hand at a distillery in Sicamous. Pretty impressive. Any idea what the advantages are of a 2 column one pot still are? Other than height saving. They had 18 plates in under 10 feet. How do they flow from one to another? Guess I should of checked it out better.
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bluefish_dist
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Re: Double Column stills

Post by bluefish_dist »

A two column still or a split column can be different. A split column is common to do vodka under a short roof. For best performance the distillate is pumped from the bottom of the second column to the top of the first. The less effective version has the second column drain to the boiler.

A two column gives more column area as there are two columns. I have seen a few photos of them, but have never seen one in action. Seems like a single larger column would work better than two smaller columns.
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LWTCS
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Re: Double Column stills

Post by LWTCS »

Hi madshine,
Originally the intent was to reduce the footprint required for a more typical divorced side column.
In this case the top side of the kettle is nothing more than the base for column #2.
Column #2 does not receive any vapor directly from the kettle. Vapor is fed over from column #1.
At the base of column #2 there is a bottoms return straw that drops below the liquid level in the kettle. This insures against vapor bipass.
The unintended benefit for this configuration is that because the side column os mounted directly to the kettle, the column experiences less heat loss and so dials on pretty quickly with good behavior.

A single column absolutely behaves better. Especially because invariably, column #2 will always be returning relatively high proof bottoms to the kettle. But not every distillery has the luxury of high ceilings needed for a tall column .

I hope this helps.
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Bushman
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Re: Double Column stills

Post by Bushman »

LWTCS, I was going to weigh in on this after seeing your set up at the ADI conference in San Diego but figured you would come along and give a better explanation. I was right! :thumbup:
Madshine
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Re: Double Column stills

Post by Madshine »

Thx LWTCS I figured it was mostly to save space. Most people probably don't have the luxury of a 20 foot ceiling to run 18 plates!
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Re: Double Column stills

Post by manu de hanoi »

LWTCS wrote:Hi madshine,
Originally the intent was to reduce the footprint required for a more typical divorced side column.
In this case the top side of the kettle is nothing more than the base for column #2.
Column #2 does not receive any vapor directly from the kettle. Vapor is fed over from column #1.
At the base of column #2 there is a bottoms return straw that drops below the liquid level in the kettle. This insures against vapor bipass.
The unintended benefit for this configuration is that because the side column os mounted directly to the kettle, the column experiences less heat loss and so dials on pretty quickly with good behavior.

A single column absolutely behaves better. Especially because invariably, column #2 will always be returning relatively high proof bottoms to the kettle. But not every distillery has the luxury of high ceilings needed for a tall column .

I hope this helps.
You should add a mini pump (sanitary gear pump for example) so that the bottom of col 2 is returned to the top of col 1.
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LWTCS
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Re: Double Column stills

Post by LWTCS »

manu de hanoi wrote:
LWTCS wrote:
You should add a mini pump (sanitary gear pump for example) so that the bottom of col 2 is returned to the top of col 1.
That would definitely increase efficiency on more than one level (notwithstanding potential mechanical failure).
*Less heat input
*Faster collection speed
*Even more stable ABV
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Re: Double Column stills

Post by OtisT »

LWTCS. Do folks with a good foundation is single column fractioning find it a challenge learning to dial in the non-pump style of double column? I’m assuming one would need to monitor head temp and reflux on both columns. Are their other unique aspects to monitor/manage with such a setup?

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LWTCS
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Re: Double Column stills

Post by LWTCS »

Hi Otis,
Its really not that hard truthfully. At least on this system.
The still jocky/ balancing act usually only comes into play if the operator does not make incremental adjustments to heat input in relation to coolant flow.
Lets just say a measured heat up when learning the behavior of the system will get you there faster than rushing to produce.

I have noticed on some other systems that the bottoms drain return back to the kettle is often under sized and that can compromise the range of operation as well as making it more difficult to get both columns to behave identically.

But basically all thats needed is to simply bring column #1 under full reflux, then back off on cooling flow enough to allow column #2 to load under full reflux.
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Re: Double Column stills

Post by OtisT »

:thumbup: :thumbup: Thanks for the info. It’s a very cool concept/design.

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Sunshineer
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Re: Double Column stills

Post by Sunshineer »

LWTCS wrote:Hi madshine,
Originally the intent was to reduce the footprint required for a more typical divorced side column.
In this case the top side of the kettle is nothing more than the base for column #2.
Column #2 does not receive any vapor directly from the kettle. Vapor is fed over from column #1.
At the base of column #2 there is a bottoms return straw that drops below the liquid level in the kettle. This insures against vapor bipass.
The unintended benefit for this configuration is that because the side column os mounted directly to the kettle, the column experiences less heat loss and so dials on pretty quickly with good behavior.

A single column absolutely behaves better. Especially because invariably, column #2 will always be returning relatively high proof bottoms to the kettle. But not every distillery has the luxury of high ceilings needed for a tall column .

I hope this helps.
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tiramisu
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Re: Double Column stills

Post by tiramisu »

I often wonder why people choose plates over spp when the density of spp is so much more efficient.
The bubble plates are very sexy but it seems like a lot of space and money for sexy.

Am I missing something?
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Re: Double Column stills

Post by Saltbush Bill »

tiramisu wrote:I often wonder why people choose plates over spp when the density of spp is so much more efficient.
The bubble plates are very sexy but it seems like a lot of space and money for sexy.
Am I missing something?
Yes you are missing the fact that SPP works best in reflux stills made for Azeo type products , Vodka / Neutral type spirits.
Plates are better for columns used to make flavoured brown spirits like Rum, Whisky and Brandy...............Two very different stills made for very different jobs.
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Re: Double Column stills

Post by LWTCS »

Saltbush Bill wrote:
tiramisu wrote:I often wonder why people choose plates over spp when the density of spp is so much more efficient.
The bubble plates are very sexy but it seems like a lot of space and money for sexy.
Am I missing something?
Yes you are missing the fact that SPP works best in reflux stills made for Azeo type products , Vodka / Neutral type spirits.
Plates are better for columns used to make flavoured brown spirits like Rum, Whisky and Brandy...............Two very different stills made for very different jobs.
Also to mention that at the commercial scale, cleaning SPP is more labor intensive.
SPP also adds a considerable amount of weight on an 18" diameter column for example.
At the commercial scale, random or structured packing mediums get very spendy.
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manu de hanoi
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Re: Double Column stills

Post by manu de hanoi »

Yes you are missing the fact that SPP works best in reflux stills made for Azeo type products , Vodka / Neutral type spirits.
Plates are better for columns used to make flavoured brown spirits like Rum, Whisky and Brandy...............Two very different stills made for very different jobs.
No, because
1-plates also require reflux in order to work
2-you can also use either less SPP height, or same height of SPP but less reflux to achieve the lesser separation of a plated column
Also to mention that at the commercial scale, cleaning SPP is more labor intensive.
SPP also adds a considerable amount of weight on an 18" diameter column for example.
At the commercial scale, random or structured packing mediums get very spendy.
yes these are valid points
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Re: Double Column stills

Post by googe »

I made one ages ago, LWTCS has a good point about drain size, mine had issues because of drain size but when stable and in tune ran great.
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