Split column design

[junglejimmy]

Hi,

So we have been running a Still Dragon Single 8' Column attached to a 200L boiler for about a year now. At the present time we are almost running it around the clock to keep up with demand. We would like to invest in a larger still and after some research i have seen that most of them are Split Column Stills. The split column stills featured on Artisan Still Design look amazing, but I am a little perplexed as to how they operate.

Is the first 4 plate column used for rums and whiskys, and the second 16 plate column used for vodka? or are the first and second column used in conjunction to give a total of 20 plates for Vodka Production?

Thanks

[junglejimmy]

So after a bit of research I have discovered that both the 4 plate column and the 16 plate column can both be used, in conjunction, for a vodka run. My next question would then be how is the operation procedure different from running a single column with a single dephlegmator?

My best guess would be this:

1. Bring the boiler up to strike temp
2. Have the dephlegmator fully open on the first column (4 plate)
3. Stack the first column with alcohol
4. Gradually close the the first dephlegmator on the first column so as to stack the second column
5. Have the dephlegmator fully open on the second column for 100% reflux
6. keep the system in equilibrium for a period of time.
7. gradually close the second dephlegmator to start releasing the heads

Is this in the ballpark guys?

[ebstauffer]

Artisan Still Design doesn't offer a split column design (I am the midwest sales rep) -- we offer a modular design which allows you to direct vapor flow to the appropriate column. Although you could position the valves to run vapor through both columns, the design intent is to use either / or -- 4-tray for whiskey, 16-tray for neutral spirits. You're hit the nail on the head in that split columns are inherently difficult to run. It can be finicky enough to modulate boiler heat / water flow to the deph to keep trays neatly stacked (not dry / not flooded) in a single column let alone two.

Eric

[Artisan Still Design]

You can run all plates for reflux

you have to think of it like a single large column

start stacking at the last plate and work back from there

it is a bit more difficult to do than a single column but one you get the proceedure down it works quite well

[John McKee]

Multi column systems become pretty necessary as you grow. We also build distillation equipment, which you can see at headframestills.com. Our standard model processes 1000g beer every 8 hours in a single pass across a 4 column system.

Cheers,

McKee

[junglejimmy]

Thanks for the info guys. your still look great. I do have another question however.

If we were to purchase a 12' column with 16 plates, what would be the optimal pot size for a 8 - 12 hour run with a 40% ABV charge?

Thanks

[Bluestone]

Off the top of my head...600 gallons or so.

[meerkat]

My limited experience with split columns confirms the procedure recommended above where the vapor from the top of the first column is taken to the base of the second column. Something which I have always seen, but which is not mentioned above (perhaps because it is too obvious?), is that the liquid from the base of the second column is pumped to the top of the first column to provide reflux for this section of the column. This introduces another variable (the second column's base level) which needs to be controlled.

In the large commercial vodka plants where I have seen split columns this is not a problem because they simply install the necessary pumps, piping and controls but I would think craft distillers would probably have to do this controlling manually. I suppose that with a 4/16 split you could simply drain the liquid from the base of the second column back to the pot via a gooseneck seal, but then how do you provide reflux for the 4 plate section?

[HedgeBird]

I suppose that with a 4/16 split you could simply drain the liquid from the base of the second column back to the pot via a gooseneck seal, but then how do you provide reflux for the 4 plate section?

I always assumed most split columns had a dephlegmator at the top of each column?

[Bluestone]

Most ASD designs include a dephlegmator on top of each column. It's simpler and more cost effective than pumping reflux back to the top of the previous column.

[meerkat]

Thanks for the replies HedgeBird and Bluestone - the dephlegmators would solve the problem. I have noticed that even in large continuous distillation plants the operators always like to have the dephlegmator / condenser combination for the extra flexibility it offers them - even if the calculations say a condenser alone would do the job.

[Artisan Still Design]

a reflux pump would be ideal, but does ad to the control complexity and cost.

gains over dual dephegmaters exists but is usually not enough to justify the additional cost.

[Brian Morton]

So I am running a 600 gallon pot with column. Its a multi column/gin setup. Do to height restrictions I have a reflux pump and holding tank. This allows reflux to fall and empty column/'s to holding tank and then pump up to still. I have done a couple runs and found that the column fills properly, stacks, and after pulling heads it runs about five gallons out and the the temp rises in the column. It is acting like it is at the end of a run. I then noticed that during the runs the reflux pump wasn't being triggered to empty the tank. Next I shut things down and then let it cool and the reflux fell and still no pump action... I checked the tri clamp the holds the pipe to the tank and as undo it starts to act like it has an air lock or some pressure issue. As soon as that stops the reflux floods the tank and pump works fine and empties the reflux into the still. This same thing happens on the next run.

So I am assuming that the column temp goes up due to water/alc content in the column and that the new vapor from still isn't able to enter into column in normal amounts due to some air lock or vapor pressue issue that has to do with the pump back.

Is there a needs relief valve for the holding tank? Or am I completely nuts and need more beer.

I hope someone has a bit of wisdom that they can share. This is the first time I have ever really posted like this. I know a lot of you and thank you in advance. -Brian