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• I wonder what size re-boiler would be needed for a typical reflux tower type still for the second stage. I would think that the max what you might need would
Message 1 of 3 , Sep 2, 2002
I wonder what size re-boiler would be needed for a typical reflux
tower type still for the second stage. I would think that the max
what you might need would be about 20% of the wash volume. Say if
you have 5 gallons at 15% wash then the size would be needed about
5*4qt/gal*0.15(%)+1qt=4quarts (1 gallon = approx. 4 liters or
quarts). For 5 gallons wash the re-boiler would be needed is about 1
gallon or 4 liters. Fot the next stage it would be 20% of 4 liters
The reason I verify this is that I want to develop a nice looking
tabletop type of reflux still. One of the features would be a re-
boiler. If I am correct this should be equal to second and third re-
distilling stages; or perhaps thumper boxes. Please give me some
input on this so I can proceed. It is not enough to have just logics
and deduction. I still need some theoretical background. All that
material I found on the net was just a descriptive narrative text
and very little theory behind.
Thank you in advance to all who would help me on this. In exchange I
will try to develop a nice looking and elegant table top still.
Cheers, Alex...
• I ve been thinking more seriously about building another column for my boiler. I have questions of course 8v) 1) The (necessarily) cooler temperature of the
Message 2 of 3 , Sep 3, 2002
I've been thinking more seriously about building another column for my
boiler. I have questions of course 8v)

1) The (necessarily) cooler temperature of the condensate dripping onto the
column packing in a N-S design must disrupt the reflux yes? Has anyone
considered the implications of this? I do recall some brief mention
somewhere (here or Tony's site I think) of not cooling the condensate too
much. Should I care?

2) Would it help to thermally insulate the condenser from the column?

I imagine that vapour management counters this by allowing you to pull off a
percentage of the distillate _before_ it is condensed. This allows the
condenser to be separate from the column. Nevertheless there is still a
separate cooling coil in the head that must be precisely controlled. On the
face of it this _seems_ more complicated, but perhaps it gives more

Decisions. Who needs them?

Aaron.
• ... The volume of the reboiler is basically irrelevant - its the amount of heat that you use thats important, and making sure that you ve sized the column to
Message 3 of 3 , Sep 3, 2002
> I wonder what size re-boiler would be needed for a typical reflux
> tower type still for the second stage.

The volume of the reboiler is basically irrelevant - its the amount of heat
that you use thats important, and making sure that you've sized the column
to suit it.

About the only time the size of the reboilers (or thumpers in a non-heated
setup) need considering is if you're not over-flowing / returning the
liquid back to the main boiler. In that case, you need to consider the %
of the streams in and out of it - eg if your main boiler is say 30L, and
you start with a wash at 15%, then you will be generating around (30*.15)
4.5L of pure alcohol. If this comes off at say 40%, then there will be
(4.5/0.4) 11.25 L entering the first reboiler. If that reboiler is then
making its vapour say at 65%, then only (4.5/0.65) 7L will leave that
reboiler - ie it will gain around 4.2 L of liquid during the run. That
could be a problem if its only sized to hold 2L. But you could use a small
container there, if you had a submerged overflow that simply returned any
excess back to the main boiler.

Why do you want to go to reboilers, and not simply use thumpers ?

Tony
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