> Just one more question... (There's always one)

One? Or two? ;-)

> De-Tuning. When you went from 18 to 12 scrubbies in

They were packed as normal, so there was an empty space at the top

> the column, did they get placed in the bottom, top or

> spread throughout the column.?

doing 'not much'.

> And yet another sneaky question.. any thoughts on what

Um.... Tony? ;-)

> difference it would make having the scrubbies at top,

> bottom or spread out through the column, would make to

> the product.?

My guess...

If the scrubbers were spread over the whole column, I think the

purity would be higher than if they were packed as 'normal', and so

leaving an empty space. My logic for this,is that there is still a

good surface area for reaction, and hence no 'wasted' space. In the

normal packing, while the surface are is more per unit volume, it

doesn't have the height.

The empty space at the top or bottom in the 'normal' packing

density.... I think the gap would be better at the top. At the

bottom it becomes just a part of the boiler in effect, so therefor

doesn't do anything. When the space is at the top, while there is

no 'reaction' occuring at the top, there is space for the purified

vapours to sit, and so I feel would be more use for it at the top

than the bottom.

That all said, I don't really know - Feel free to diagree with me!

Matt (Bris)> Um.... Tony? ;-)

likewise, I'd just be guessing. The theory doesn't help here. Can't

really say whether the gap would be better top or bottom - you can dream up

arguments for either case.

I'd rather that the remaining scrubbers were instead spread out more

sparsely, to fill the volume. Its likely to give a lesser efficiency than

a properly packed column, but might (??) be better than a half-n-half

version, as its still encouraging the liquid to drip from spot to spot,

rather than doing a big rush through the unpacked space. It also just

gives a bit more physical space for any different species / concentrations

to stay apart from each other.

Coupled with this though has to be how much you've decreased the reflux

ratio by - for an example, if you dudn't remove much packing, and kept the

reflux rate high, you may not notice much "detuning". When I run my still

for rum, I keep the same packing in it, but really knock back the reflux

ratio heaps - like you - into the high 70's (C)

Tony

http://homedistiller.org- Hi again Matt,

Thanx yet again for an excellent reply.

I agree with what you said as far as de-tuned packing

placement is concerned.

I just had *one* more question..

As column packing height has a direct correlation to

the number of theoretical plates, what was the height

of your packing in your 50mm column.?

Cheers

AuntyEthyl

--- mattdistiller <distiller@...> wrote:>

__________________________________________________

> > Just one more question... (There's always one)

>

> One? Or two? ;-)

>

> > De-Tuning. When you went from 18 to 12 scrubbies

> in

> > the column, did they get placed in the bottom, top

> or

> > spread throughout the column.?

>

> They were packed as normal, so there was an empty

> space at the top

> doing 'not much'.

>

> > And yet another sneaky question.. any thoughts on

> what

> > difference it would make having the scrubbies at

> top,

> > bottom or spread out through the column, would

> make to

> > the product.?

>

> Um.... Tony? ;-)

>

> My guess...

>

> If the scrubbers were spread over the whole column,

> I think the

> purity would be higher than if they were packed as

> 'normal', and so

> leaving an empty space. My logic for this,is that

> there is still a

> good surface area for reaction, and hence no

> 'wasted' space. In the

> normal packing, while the surface are is more per

> unit volume, it

> doesn't have the height.

>

> The empty space at the top or bottom in the 'normal'

> packing

> density.... I think the gap would be better at the

> top. At the

> bottom it becomes just a part of the boiler in

> effect, so therefor

> doesn't do anything. When the space is at the top,

> while there is

> no 'reaction' occuring at the top, there is space

> for the purified

> vapours to sit, and so I feel would be more use for

> it at the top

> than the bottom.

>

> That all said, I don't really know - Feel free to

> diagree with me!

>

> Matt (Bris)

>

>

Do You Yahoo!?

Yahoo! Sports - sign up for Fantasy Baseball

http://sports.yahoo.com - I replied, but the email seems to have got lost in the ether, so I

will try again.

> Thanx yet again for an excellent reply.

No problems - I am only shooting from the hip though!

> I just had *one* more question..

Just one? ;-)

> As column packing height has a direct correlation to

Normally, for vodka, my column is packed to 1.2 m with 18 large

> the number of theoretical plates, what was the height

> of your packing in your 50mm column.?

scrubbers. For the 'de-tuned' run, it is 0.9m with 12 scrubbers.

I think not only is the packed height important, but also the packed

density. If it is assumed that all s/s scrubbers have similar thread

sizes, this can easily be calculated by weighing the scrubbers, and

calculating the volume of the packed height. Density=weight/volume.

If the assumption that all s/s scrubbers have similar thread sizes is

true, then the density is directly proportional to the surface area,

but a lot easier to calculate!

My scrubbers weigh 14.1g each (I just weighed them all and divided it

out), so 18 scrubbers weigh 0.2546kg and 12 scrubbers weigh 0.1697kg.

The volume of the 50mm column is easy = pi * r^2 * height

1.2m - volume=0.002356 m^3

0.9m - volume=0.001767 m^3

So the density=weight/volume:

1.2m with 18 scrubbers = 108.1 kg/m^3

0.9m with 12 scrubbers = 96.1 kg/m^3

So, in my case, the 1.2m packing height, whilst being higher packed,

is also more densely packed (=more surface area) - I guess because

the weight of the scrubbers compress the ones below? Whatever the

reason, the difference is over 10%, so there could definitely be an

effect.

I see a really neat experiment that could be done here, with the same

packed height column, and different densities (=surface area) of

scrubbers. There has to be an optimal packing density (=surface

area), which would probably be fairly easy to work out through

experimentation.

OK. Enough from me. I hope that answers your question in a long

handed way!

Matt (Bris) > I see a really neat experiment that could be done here, with the same

Hurray ! something a bit more precise than the "breath through" test

> packed height column, and different densities (=surface area) of

> scrubbers. There has to be an optimal packing density (=surface

> area), which would probably be fairly easy to work out through

> experimentation.

Tony