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## Advantage of tall column

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- 0 Attachment

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- 0 Attachment

--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>

wrote:>

If you double the available volume to fill per timeslice, then you can

> 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

>

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- 0 Attachment

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:>

foot

> --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@>

> wrote:

> >

> > What would be the advantage of having a 10 foot column over a 5

> > column? Would i be able to put more power through it? Would it

just

> > sepperate better? Are there any disadvantages?

can

> >

> > -Tyler

> >

>

>

>

> If you double the available volume to fill per timeslice, then you

> double the power input (approx). Disadvantages are: More expense

in

> materials; more insulation is necessary.

amount

>

> The usual method of designing a column is first to decide what

> 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,

amount of

> because it's necessary to perform total reflux for a certain

> time before taking product.

>

>

> Slainte!

> regards Harry

>- 0 Attachment

--- In new_distillers@yahoogroups.com, "fit_dude42" <fit_dude42@...>

wrote:>

still

> Maybe i misunderstood some of the info when i was building my

> but please correct me if i'm wrong.

HETP

>

> The height of the column combined with the type of packing

> controlled the purity %age of the product, as you get a higher

> 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.

>

...........Ever seen the steam fly out of a pressure cooker when you

> 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,

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.

>

involved?

> Have i got this wrong, or just misunderstood the principles

>

Slainte!

> Karl.

>

> Cheers m'dears.

regards Harry- 0 Attachment

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

home page, but hadn't quite worked out why it did what it did.

Many thanks,

Karl.

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

wrote:>

more

> --- 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,

> plates.

a

> 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

> > smaller diameter column would not flow as much vapour as a

larger

> > diameter column,

you

>

>

>

> ...........Ever seen the steam fly out of a pressure cooker when

> 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

produce.

> 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

>

flow

>

>

> ........Vapour VOLUME CREATED is governed by power input. The

> 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

>- 0 Attachment

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

>- 0 Attachment

--- In new_distillers@yahoogroups.com, "abbababbaccc"

<abbababbaccc@...> wrote:>

And this is because taller columns have more theoretical plates

> 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.

(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- 0 Attachment

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:>

numerically

> --- In new_distillers@yahoogroups.com, "abbababbaccc"

> <abbababbaccc@> wrote:

> >

> > the biggest

> > advantage to tall columns as I see it is that you can run

> > lower reflux ratio to get similar results as with shorter columns.

at

> > 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

> 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

>- 0 Attachment

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:>

to

> 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

> use more ower input, right? Would i possibly be able to go up to

input,

> 5.5kw like the PDA-2? I am assuming that if i raise the power

> then i would not be able to reduce the reflux ratio. I am a little

the

> confused by your reference to HETP and "plates". I thought it was

> 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

>

>

>- 0 Attachment

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:>

to

> 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

> use more ower input, right? Would i possibly be able to go up to

input,

> 5.5kw like the PDA-2? I am assuming that if i raise the power

> then i would not be able to reduce the reflux ratio. I am a little

the

> confused by your reference to HETP and "plates". I thought it was

> 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

>

>

>- 0 Attachment

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- 0 Attachment

--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>

wrote:>

reflux

> 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

> 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

of

> over 2-3kw, why is it that the PDA-2 will handle a max power input

> 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".

>

of

> Once again, to make sure that i get the entirely clear definition

> HETP, the HETP is the height of packing that it takes to equal one

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

> 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.

.......Yes.

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

..Yes.

>

years

> I do wonder, how does one aquire this knowledge? Does it take

> 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!"

Slainte!

>

> -Tyler

>

regards Harry- 0 Attachment

--- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...> wrote:>

snip

> 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? >

> -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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