Improve the Smiley design?

[pli]

Ian Smiley’s book describes building a reflux still based on 1-1/4” dia. copper tubing. The short review of the book on THIS website says, if using a heat source of 1500 watts, his design would be more efficient if the column diameter were increased to 2”. Okay. Then probably reduce the column height, right? And what about the head – leave it as is… including Liebig dimensions… or proportionately scale up the head to match the column?

[tracker0945]

Input heat is matched to column diameter, therefore the suggestion is that for 1800w of power, a 2" column would be a better match rather than 1 1/2".
Column height is matched to purity therefore it does not follow that if you change the diameter you must change the height.


Cheers.

[Hawke]

I have seen figures of 12:1 to 24:1 hieght to diameter ratios for reflux stills. So by going from 1 1/2 to 2", you should increase the length of a column. Diameter = speed of collection, packed hieght = purety.

[Mud]

Hey Hawke,
That range of ratios pops up now and again. Husker, you, and several others have all mentioned it. Where does it come from?

-Mud

[Hawke]

Mud,
Think it comes from Ian's book. Too cheap to buy it though.
My Boka mini has a ratio of about 20:1 and is way easier to get 95%+ out of than my Valved reflux at 14:1.

[bronzdragon]

I run a 1500w hotplate as my heating source on a 5 gal boiler and I have a two stage column. When in pot mode it is about 18" and when in full column mode it is about double that at 35"-40" somewhere...sorry I don't have exact measurements and don't feel like getting up from my desk right now.

I like the way it runs better in full column mode (35"-40").
And it is 2" in diameter.

If that helps any.

~bd~

[Mud]

I was guessing either Making Pure Corn Whiskey or The Compleat Distiller. But I'm too cheap to buy them, too.

Taller is better up to a point. Check out the calcs to find that height based on your packing, but 10 theoretical plates is about as good as it gets. Shorter and you need more reflux, taller and you see almost no more improvement.

[rad14701]

I need to find where I read those figures and bookmark them... I've read about them on more sites than just this one... Normal range being 12:1 - 24:1 with anything over 30:1 - 36:1 either yielding no improvement or reducing overall efficiency... I'm sure someone with a multi-section column could verify these within a fair amount of approximation...

I seem to recall someone running a 2" X 60" column and then trying 72" with no appreciable benefit...