Fractioning efficiency

zeff · Post by **zeff** » Tue Sep 12, 2006 8:31 pm

Just wondered if anyone had any ideas on this....

My first fractioning still used a 50L ss keg boiler with an 1800w element. It had a 1.5", 1.6m column packed with ss scrubbers and was the original nixon stone set up with a 90 degree elbow connecting the tee peice at the top of the column to the condensor. Ive just made a new column attached to the same boiler with the same element but this time its a 2" column 1.8m tall with two tee peices connecting the column to the condensor.

http://homedistiller.org/equip/photos-ns" onclick="window.open(this.href);return false;" rel="nofollow - on this page my first column is similair to matts offset-head still and my second is similair to Dicks still.

So the difference between my new and old column is that the new one is longer and wider and also the reflux that isnt collected is directed to fall down the centre of the column instead of running down the side. All these differences i thought would have allowed me to collect spirit faster but with my old still i could collect at 70mls/min @ 96% for the first bottle whereas now i can only do 30mls/min for the first bottle.

If anyone can decipher this post and can think of any reasons why my new column is less efficient than my old one it would be much appreciated...thanks

decoy · Post by **decoy** » Tue Sep 12, 2006 9:02 pm

only thing i can think of is that by having a smaller diameter column before packed with scrubbers increased the presure inside the boiler efectivly increasing the temperature that your wash was boiling at internaly also increasing the rate of alcohol evaporation also forcing steam out at a faster rate..

only thing that i can think of... maybe somone else can be of more help.

markx · Post by **markx** » Wed Sep 13, 2006 12:06 am

Placement, density and shape of the packing elements also makes a big diffrence. If you pack a column too tight you may flood it at fairly low heat inputs and lose efficency. Then again pack it too loose and again efficency is lost. Well.....practice is always an art and it never completely corellates with any theory. Experiment with your setup.....try repacking the column, changing the direction or shape of the reflux flow, vary the heat input etc.

copperhead · Post by **copperhead** » Wed Sep 13, 2006 3:47 am

needel valves in the reflux and take off tubes will give you more control and likely improve your efficency.

rkr · Post by **rkr** » Wed Sep 13, 2006 4:57 am

Do you have your column insulated? If not that's probably the reason for your poor performance. With smaller column the increased vporspeed will somewhat negate the negative side effects of uninsulated column.

Another thing, you are feeding the reflux on top of the packing aren't you?

Cheers, Riku

zeff · Post by **zeff** » Fri Sep 15, 2006 3:44 am

yep the reflux is directed straight into the top of the column packing. Its not insulated because i tried my 1.5" column without packing and never had any problems so i might try insulating it. I have a suspicion now that its the packing, i did it a bit tighter than my old column, so i might repack it...thanks for the suggestions guys

zeff · Post by **zeff** » Mon Oct 02, 2006 10:08 pm

Im just doing another run after repacking the column and insulating it and im running it pretty slowly and its coming out at 95% but i can still smell fusels in there...any thoughts?

markx · Post by **markx** » Tue Oct 03, 2006 1:23 am

You packed it with SS scrubbers, right? Try copper ones if everything else fails. Copper tends to break up some of the funky stuff in the alcohol. But make sure they are pure copper not plated ones. Pure copper scrubbers don't attract magnets and they have a dull texture whereas the plated ones are shiny.

You could also try increasing the heat input...a 2" column can handle about 2.5kW of power when not overly packed.

rkr · Post by **rkr** » Tue Oct 03, 2006 2:51 am

markx wrote: You could also try increasing the heat input...a 2" column can handle about 2.5kW of power when not overly packed.

2.5 kW to 2" column makes for 36"/s vaporspeed. A column packed with scrubbers/mesh will typically flood in 22-28"/s range. The max. recommended power for 2" column is 1500kW + heat losses (22"/s), even that will seriously degrade separation efficiency.

Cheers, Riku

Uncle Remus · Post by **Uncle Remus** » Tue Oct 03, 2006 6:44 am

Im just doing another run after repacking the column and insulating it and im running it pretty slowly and its coming out at 95% but i can still smell fusels in there...any thoughts?

What did you make your wash with? If you used turbo yeast you probably won't get rid of the off smell/ flavour without carbon filtering. This has been my experience anyway. I don't use turbos anymore for this reason.

markx · Post by **markx** » Wed Oct 04, 2006 12:55 am

2.5 kW to 2" column makes for 36"/s vaporspeed. A column packed with scrubbers/mesh will typically flood in 22-28"/s range. The max. recommended power for 2" column is 1500kW + heat losses (22"/s), even that will seriously degrade separation efficiency.

I just spoke of personal experience with my own setup, because my 2.5" column handles 3.2kW at full steam and does not flood itself.....have not found that increasing heat input (below the flooding point of course) will degrade fractioning efficency much or move the cutpoints. So I figure that given similar circumstances 2kW should work without flooding zeff's setup. But of course I might be wrong since the maximum heat input is highly dependant on the density and geometry of the packing. I guess it's just trial and error to figure out what parameters work best for a given apparatus. And they all tend to have their own character...

hummelfahrer · Post by **hummelfahrer** » Wed Oct 04, 2006 2:04 pm

Howdy,
@rkr:I' sure that you meant 1500W, not kW, for the 2" tower.
Keep up the good work though;I have read all of your postings and learned a lot.Thanx
C U
hf

rkr · Post by **rkr** » Wed Oct 04, 2006 8:40 pm

Hummelfahrer, yes I meant wats, not kilowats. Sorry about that.

Markx, I think the difference in values here lies in heat losses. I'm talking about the power that actually enters the column, not total power. How large boiler do you have, what material is it made of and how is it insulated?

Cheers, Riku

markx · Post by **markx** » Thu Oct 05, 2006 12:27 am

I'm talking about the power that actually enters the column, not total power.

Yea.....that may be the case, but I don't think that I'm losing practically half of the heat since my setup is fully insulated. The column is covered in tube insulation and the boiler is wrapped in a thick blanket during the run. All the parts are stainless except the copper packing in the column. And stainless conducts heat rather poorly since the boiler stays hot for about 24h after the heat has been shut off (and the blanket removed).

That's my current setup

http://homedistiller.org/forum/viewtopic.php?t=2933

rkr · Post by **rkr** » Thu Oct 05, 2006 1:05 am

markx wrote:
I'm talking about the power that actually enters the column, not total power.
Yea.....that may be the case, but I don't think that I'm losing practically half of the heat since my setup is fully insulated. The column is covered in tube insulation and the boiler is wrapped in a thick blanket during the run. All the parts are stainless except the copper packing in the column. And stainless conducts heat rather poorly since the boiler stays hot for about 24h after the heat has been shut off (and the blanket removed).

That's my current setup

http://homedistiller.org/forum/viewtopic.php?t=2933

Nice glass section. I almost wish I had one to experiment with. Well, I guess I'll settle for my 4" column for now

What you say seems to work OK albeit being on the limit. Assuming modest heat losses of 200W (in practise VERY hard to achieve) you'll be running at 3kW and that with 64mm column gives you a vaporspeed of 27.5"/s which is indeed achievable with loose enough packing. You said it's just below flooding limit, right?

I've done some experiments with 64mm columns and while the high vaporspeed works you'll get much better separation (i.e. larger middle cut) if you turn the power down to 1500W or so. If you are happy with the quality you get now, by all means let her rip at full power

Cheers, Riku

markx · Post by **markx** » Mon Oct 09, 2006 1:53 am

It must be quite close to flooding point with current parameters applied, but I've not managed to flood it yet (no means available to pump more power into the boiler without blowing the fuses

).

At first my column was packed real tight (I had rammed almost 80 scrubbers into the 1.7m column) and it became flooded and lost separation even at 1200W which was a ridiculous result by my understanding. So I removed almost a third of the packing and rearranged the srubbers for maximum uniformity. Now it works fine, works alot faster to be exact. Turning down the power to 1500W means practically to double the duration of the run, but it does not double the separation efficency. With double the time I can manage a second run for the feints (by filling the hot boiler with feints through the lower thermometer port on the column) and still get more out of it. But it's just my personal opinion and should by no means be taken as the absolute truth

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Fractioning efficiency

Fractioning efficiency

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