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• What would be the advantage of having a 10 foot column over a 5 foot column? Would i be able to put more power through it? Would it just sepperate better? Are
Message 1 of 13 , Oct 30, 2006
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What would be the advantage of having a 10 foot column over a 5 foot
column? Would i be able to put more power through it? Would it just
sepperate better? Are there any disadvantages?

-Tyler
• ... If you double the available volume to fill per timeslice, then you can double the power input (approx). Disadvantages are: More expense in materials;
Message 2 of 13 , Oct 31, 2006
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--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
wrote:
>
> What would be the advantage of having a 10 foot column over a 5 foot
> column? Would i be able to put more power through it? Would it just
> sepperate better? Are there any disadvantages?
>
> -Tyler
>

If you double the available volume to fill per timeslice, then you can
double the power input (approx). Disadvantages are: More expense in
materials; more insulation is necessary.

The usual method of designing a column is first to decide what amount
of product per hour you want to produce. Then design a column, HETP
and power input that will achieve that rate and purity; then design a
condenser that will accomodate that power input for total reflux,
because it's necessary to perform total reflux for a certain amount of
time before taking product.

Slainte!
regards Harry
• Maybe i misunderstood some of the info when i was building my still but please correct me if i m wrong. The height of the column combined with the type of
Message 3 of 13 , Oct 31, 2006
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Maybe i misunderstood some of the info when i was building my still
but please correct me if i'm wrong.

The height of the column combined with the type of packing
controlled the purity %age of the product, as you get a higher HETP
from a taller column and greater height of packing.

The column diameter was the primary limitation on vapour flow so a
smaller diameter column would not flow as much vapour as a larger
diameter column, and vapour flow was controlled by how much power
was being used in the boiler i.e. how much vapour it could produce.

Have i got this wrong, or just misunderstood the principles involved?

Karl.

Cheers m'dears.

--- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
wrote:
>
> --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@>
> wrote:
> >
> > What would be the advantage of having a 10 foot column over a 5
foot
> > column? Would i be able to put more power through it? Would it
just
> > sepperate better? Are there any disadvantages?
> >
> > -Tyler
> >
>
>
>
> If you double the available volume to fill per timeslice, then you
can
> double the power input (approx). Disadvantages are: More expense
in
> materials; more insulation is necessary.
>
> The usual method of designing a column is first to decide what
amount
> of product per hour you want to produce. Then design a column,
HETP
> and power input that will achieve that rate and purity; then
design a
> condenser that will accomodate that power input for total reflux,
> because it's necessary to perform total reflux for a certain
amount of
> time before taking product.
>
>
> Slainte!
> regards Harry
>
• ... still ... HETP ... ...................Same power input, taller column = same HETP, more plates. More power input, taller column = expanded HETP (each plate
Message 4 of 13 , Oct 31, 2006
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--- In new_distillers@yahoogroups.com, "fit_dude42" <fit_dude42@...>
wrote:
>
> Maybe i misunderstood some of the info when i was building my
still
> but please correct me if i'm wrong.
>
> The height of the column combined with the type of packing
> controlled the purity %age of the product, as you get a higher
HETP
> from a taller column and greater height of packing.

...................Same power input, taller column = same HETP, more
plates.
More power input, taller column = expanded HETP (each plate is
taller/deeper), less plates for given height.

>
> The column diameter was the primary limitation on vapour flow so a
> smaller diameter column would not flow as much vapour as a larger
> diameter column,

...........Ever seen the steam fly out of a pressure cooker when you
remove the wobbler valve? That's a very small aperture it's coming
from (think small diam column), and it doesn't bother the steam
volume at all. But it DOES have a marked bearing on the SPEED
upwards of said steam.

and vapour flow was controlled by how much power
> was being used in the boiler i.e. how much vapour it could produce.

........Vapour VOLUME CREATED is governed by power input. The flow
of the vapour only changes speed-wise, not volume-wise. See above.

>
> Have i got this wrong, or just misunderstood the principles
involved?
>
> Karl.
>
> Cheers m'dears.

Slainte!
regards Harry
• I stand corrected. I knew what i was trying to say just didn t get the terms right. The HETP will of course be the same it will just mean you have more
Message 5 of 13 , Oct 31, 2006
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I stand corrected. I knew what i was trying to say just didn't get
the terms right. The HETP will of course be the same it will just
mean you have more effective plates, which i believe would alter the
%age?

What i meant to say was that i had thought that the wider the column
the more it can cope with without blowing the whole lot out the top
due to the vapour rising under the higher power of the boiler?

Does that make more correct sense?

I built my still along the Bokakob 'mini-still' design but with a
wider and taller column, using the very useful calculators on the

Many thanks,

Karl.

--- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
wrote:
>
> --- In new_distillers@yahoogroups.com, "fit_dude42" <fit_dude42@>
> wrote:
> >
> > Maybe i misunderstood some of the info when i was building my
> still
> > but please correct me if i'm wrong.
> >
> > The height of the column combined with the type of packing
> > controlled the purity %age of the product, as you get a higher
> HETP
> > from a taller column and greater height of packing.
>
>
>
>
> ...................Same power input, taller column = same HETP,
more
> plates.
> More power input, taller column = expanded HETP (each plate is
> taller/deeper), less plates for given height.
>
>
>
> >
> > The column diameter was the primary limitation on vapour flow so
a
> > smaller diameter column would not flow as much vapour as a
larger
> > diameter column,
>
>
>
> ...........Ever seen the steam fly out of a pressure cooker when
you
> remove the wobbler valve? That's a very small aperture it's
coming
> from (think small diam column), and it doesn't bother the steam
> volume at all. But it DOES have a marked bearing on the SPEED
> upwards of said steam.
>
>
> and vapour flow was controlled by how much power
> > was being used in the boiler i.e. how much vapour it could
produce.
>
>
>
> ........Vapour VOLUME CREATED is governed by power input. The
flow
> of the vapour only changes speed-wise, not volume-wise. See above.
>
>
>
> >
> > Have i got this wrong, or just misunderstood the principles
> involved?
> >
> > Karl.
> >
> > Cheers m'dears.
>
>
>
> Slainte!
> regards Harry
>
• This is true up to a point of column flooding. However, the biggest advantage to tall columns as I see it is that you can run numerically lower reflux ratio to
Message 6 of 13 , Oct 31, 2006
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This is true up to a point of column flooding. However, the biggest
advantage to tall columns as I see it is that you can run numerically
lower reflux ratio to get similar results as with shorter columns.
This in turn translates to a faster distillation.

Cheers, Riku

--- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...> wrote:

>
>
> If you double the available volume to fill per timeslice, then you can
> double the power input (approx). Disadvantages are: More expense in
> materials; more insulation is necessary.
>
> The usual method of designing a column is first to decide what amount
> of product per hour you want to produce. Then design a column, HETP
> and power input that will achieve that rate and purity; then design a
> condenser that will accomodate that power input for total reflux,
> because it's necessary to perform total reflux for a certain amount of
> time before taking product.
>
>
> Slainte!
> regards Harry
>
• ... And this is because taller columns have more theoretical plates (obviously). Thus there are more distillations/separations as the vapour traverses the
Message 7 of 13 , Oct 31, 2006
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--- In new_distillers@yahoogroups.com, "abbababbaccc"
<abbababbaccc@...> wrote:
>
> the biggest
> advantage to tall columns as I see it is that you can run numerically
> lower reflux ratio to get similar results as with shorter columns.
> This in turn translates to a faster distillation.

And this is because taller columns have more theoretical plates
(obviously). Thus there are more distillations/separations as the
vapour traverses the column length. So when you finally start
returning reflux, that returned mixture is far more concentrated in
ethanol than would be available in a shorter column. Therefore you
can afford to lower the ratio.

In theory, a column of sufficient length should require no reflux at
all, as the product arriving at the top would already be azeotrope.
However in practice, some reflux is desirable to provide the initial
downward-flowing liquid to initiate the separation/reboiling process.
Multiple-distillation fractionating columns (our 'reflux' type
stills), are a two-way action.

Slainte!
regards Harry
• Ow, my head is starting to hurt. Too much technical talk. lol. So if i have a 10 foot column of 2 copper pipe, i should be able to use more ower input, right?
Message 8 of 13 , Oct 31, 2006
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Ow, my head is starting to hurt. Too much technical talk. lol.

So if i have a 10 foot column of 2" copper pipe, i should be able to
use more ower input, right? Would i possibly be able to go up to
5.5kw like the PDA-2? I am assuming that if i raise the power input,
then i would not be able to reduce the reflux ratio. I am a little
confused by your reference to HETP and "plates". I thought it was the
same thing? I under stand that the more power, the more spead out the
plates are, therfore, you are limited by the hight of the column as
to how many plates you can have depending on you input power.

-Tyler

--- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
wrote:
>
> --- In new_distillers@yahoogroups.com, "abbababbaccc"
> <abbababbaccc@> wrote:
> >
> > the biggest
> > advantage to tall columns as I see it is that you can run
numerically
> > lower reflux ratio to get similar results as with shorter columns.
> > This in turn translates to a faster distillation.
>
>
> And this is because taller columns have more theoretical plates
> (obviously). Thus there are more distillations/separations as the
> vapour traverses the column length. So when you finally start
> returning reflux, that returned mixture is far more concentrated in
> ethanol than would be available in a shorter column. Therefore you
> can afford to lower the ratio.
>
> In theory, a column of sufficient length should require no reflux
at
> all, as the product arriving at the top would already be
azeotrope.
> However in practice, some reflux is desirable to provide the
initial
> downward-flowing liquid to initiate the separation/reboiling
process.
> Multiple-distillation fractionating columns (our 'reflux' type
> stills), are a two-way action.
>
>
> Slainte!
> regards Harry
>
• A mesh/scrubber packed 2 column will flood at somewhere inbetween 2- 3kW. However, with 10 foot column you should be able to run at ~2kW and get more than
Message 9 of 13 , Oct 31, 2006
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A mesh/scrubber packed 2" column will flood at somewhere inbetween 2-
3kW. However, with 10 foot column you should be able to run at ~2kW
and get more than twice the output you'd get with 1 meter column
running at 1kW. In practise you should be able to run 2:1 or even
lower RR at the beginning instead of 5:1 or so that's typical. The
HETP is Height Equivalent To Plate. HETP is a function of packing
efficiency, vaporspeed and reflux ratio. And no, I don't have a
formula for that.

Cheers, Riku

--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
wrote:
>
> Ow, my head is starting to hurt. Too much technical talk. lol.
>
> So if i have a 10 foot column of 2" copper pipe, i should be able
to
> use more ower input, right? Would i possibly be able to go up to
> 5.5kw like the PDA-2? I am assuming that if i raise the power
input,
> then i would not be able to reduce the reflux ratio. I am a little
> confused by your reference to HETP and "plates". I thought it was
the
> same thing? I under stand that the more power, the more spead out
the
> plates are, therfore, you are limited by the hight of the column as
> to how many plates you can have depending on you input power.
>
> -Tyler
>
>
>
• A mesh/scrubber packed 2 column will flood at somewhere inbetween 2- 3kW. However, with 10 foot column you should be able to run at ~2kW and get more than
Message 10 of 13 , Oct 31, 2006
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A mesh/scrubber packed 2" column will flood at somewhere inbetween 2-
3kW. However, with 10 foot column you should be able to run at ~2kW
and get more than twice the output you'd get with 1 meter column
running at 1kW. In practise you should be able to run 2:1 or even
lower RR at the beginning instead of 5:1 or so that's typical. The
HETP is Height Equivalent To Plate. HETP is a function of packing
efficiency, vaporspeed and reflux ratio. And no, I don't have a
formula for that.

Cheers, Riku

--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
wrote:
>
> Ow, my head is starting to hurt. Too much technical talk. lol.
>
> So if i have a 10 foot column of 2" copper pipe, i should be able
to
> use more ower input, right? Would i possibly be able to go up to
> 5.5kw like the PDA-2? I am assuming that if i raise the power
input,
> then i would not be able to reduce the reflux ratio. I am a little
> confused by your reference to HETP and "plates". I thought it was
the
> same thing? I under stand that the more power, the more spead out
the
> plates are, therfore, you are limited by the hight of the column as
> to how many plates you can have depending on you input power.
>
> -Tyler
>
>
>
• ok, so a 2 column flooding around 3kw is like my 1/2 liebig choking at 1.5kw when i tried to us it as a verticle reflux condenser, right? Too much liquid
Message 11 of 13 , Oct 31, 2006
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ok, so a 2" column "flooding" around 3kw is like my 1/2"
liebig "choking" at 1.5kw when i tried to us it as a verticle reflux
condenser, right? Too much liquid being condensed and staying in the
packing, which would impeed the vapor flow, and preasurize the still,
if i understand correctly. Which brings up another question. If your
info is correct, that a 2" column will flood if given a heat input
over 2-3kw, why is it that the PDA-2 will handle a max power input of
5.5kw? If i remember correctly, it is constucted with 2" pipe.

Once again, to make sure that i get the entirely clear definition of
HETP, the HETP is the height of packing that it takes to equal one
theoretical plate for the given tamperature, for that type of
packing? So, lets say, if the HETP for my still and its packing was 8
inches for each plate, if i increased my heat input, it might require
12 inches for each plate. I know that the measurements are not
correct, i am just wondering if i have the general idea down.

I do wonder, how does one aquire this knowledge? Does it take years
of engineering school, or is it just a matter of knowing the right
equations? I'm sorry if i am really slow with catching on to some of
the theory here, but thats why i'm in the "new distillers" forum, and
i really appreciate all of your help. Someday, i want you all to be
able to look back at me and say, "my god, what have we done!"

-Tyler
• ... reflux ... the ... still, ... your ... of ... ...........It s not 2 pipe. I can t remember which it is, either it s 3 or 4 , but definitely not 2 . ...
Message 12 of 13 , Nov 1, 2006
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--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
wrote:
>
> ok, so a 2" column "flooding" around 3kw is like my 1/2"
> liebig "choking" at 1.5kw when i tried to us it as a verticle
reflux
> condenser, right? Too much liquid being condensed and staying in
the
> packing, which would impeed the vapor flow, and preasurize the
still,
> if i understand correctly. Which brings up another question. If
your
> info is correct, that a 2" column will flood if given a heat input
> over 2-3kw, why is it that the PDA-2 will handle a max power input
of
> 5.5kw? If i remember correctly, it is constucted with 2" pipe.

...........It's not 2" pipe. I can't remember which it is, either
it's 3" or 4", but definitely not 2".

>
> Once again, to make sure that i get the entirely clear definition
of
> HETP, the HETP is the height of packing that it takes to equal one
> theoretical plate for the given tamperature, for that type of
> packing?

.............AND that particular heat input.

So, lets say, if the HETP for my still and its packing was 8
> inches for each plate, if i increased my heat input, it might
require
> 12 inches for each plate.

.......Yes.

I know that the measurements are not
> correct, i am just wondering if i have the general idea down.

..Yes.

>
> I do wonder, how does one aquire this knowledge? Does it take
years
> of engineering school,

......The discipline is known as "Chemical Engineering" ChE for
short.

or is it just a matter of knowing the right
> equations?

........ You can be 'self-taught' if you have a capacity to learn.
The information is available in any library and in many places on
the internet. I am self taught when it comes to physics,
electrical, mechanical & chemical engineering. My degrees are in
computing and Information Technology. But that doesn't stop me from
acquiring the knowledge I need to assist me in my chosen hobby.
Bottom line is, if you have a desire to learn, and a capable brain,
then the sky's the limit. Age is no barrier.

Side note for Riku: There are formulae for working out HETP.
They're called McCabe-Theile Diagrams, phase diagrams, and for the
lazy ones, computer simulations such as HYSIS . But you need to get
a lot more theory & prac under your belt (distillation-wise) before
you tackle that level. The 'net is your fingertip library. ;-)

I'm sorry if i am really slow with catching on to some of
> the theory here, but thats why i'm in the "new distillers" forum,
and
> i really appreciate all of your help.

.......Look on Tony's homedistiller.org homesite (homepage of this
group). That will give you a jump-start to the theory.

Someday, i want you all to be
> able to look back at me and say, "my god, what have we done!"
>
> -Tyler
>

Slainte!
regards Harry
• ... snip ... snip ... Hi, tyler, One of the best ways of learning is to ask the right questions of the right people. This is really interesting stuff, and
Message 13 of 13 , Nov 1, 2006
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--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...> wrote:
>
> ok, so a 2" column "flooding" around 3kw is like my 1/2"
> liebig "choking" at 1.5kw when i tried to us it as a verticle reflux

snip
>
> I do wonder, how does one aquire this knowledge? >
snip
> -Tyler
>

Hi, tyler,
One of the best ways of learning is to ask the right questions of the
right people.

This is really interesting stuff, and thanks to you and the people who
have replied to your questions we are getting a different perspective
on theory and that's really good, too.
Thanks

The Baker
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