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Author: Subject: Packing a Condenser with GAC (and other materials)
chinawhite
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[*] posted on 10-9-2009 at 07:21
Packing a Condenser with GAC (and other materials)


Hello folks,

I'm new to this forum and finding it quite an interesting space. I live in Vietnam and distilling food grade ethanol seems to be a national pasttime.

I use labware for my fractional distallation. Basically:- a 2lt ball flask with semi-circular, electric heating element, an Allihn condenser packed with stainless steel pot scrubbers as a reflux column, a Graham condenser as the condenser the connexting bits and vasaline as a 29mm ground joint grease.

I plan to polish the bulk alcohol through a split chamber water filter system that usesd a sintered ceramic filter as a prefilter, an AC/Sand/Gravel/AC column as the main filter, and (undecided at this stage) a stone filter as a remineralzation filter before storing in a water fountain dispenser with built in chiller.

My question, (I'm not to comfortable with the water filter system) is can I use a packed column to polish the alcohol vapour at the time of condensation?

I'm thinking to sub out the Graham condenser and replace it with another Allihn column, end corked with stainless steel pot scrubbers, and filled partly with coarse grit sand upstream and GAC downstream. the sand would act as condensing site to convert vapour to liquid, and the GAC as the filtsr to polish the resultant distilate.

Your thoughts would be most welcome.
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[*] posted on 10-9-2009 at 07:40


what does GAC stand for?




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chinawhite
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[*] posted on 10-9-2009 at 08:22
GAC?


Granulated Activated Carbon
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Nicodem
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10-9-2009 at 08:37
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[*] posted on 10-9-2009 at 12:50


I don't like sticking things in condensers, but hey. Whaddyado.



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[*] posted on 10-9-2009 at 14:30


Filter to polish the distillate?
What do you mean?




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[*] posted on 10-9-2009 at 15:27


It works fine. Make sure you pack everything (particularly resins) pre-wet in slurry form. Expanding packing can (and has caused, in my observation) the explosion of a column which was packed dry then made wet. A glass wool plug is sufficient to keep the GAC in there (make sure you wash it well to remove the fines first).

Keep in mind that the average 24/40 condenser can't hold that much adsorbent. A column with a stop-cock is far superior and is much easier to control. Residence time and a non-channelling plug-flow is required for best performance.

The adsorption isotherms for carbon demonstrate much greater efficiency at greater temperatures (say 60-80 °C). This would be limited, of course, by the BP of the fluid passing though there. This is why we frequently use jacketed columns with a recirculating bath (in our case, for decolorizing sugar liquor).

A friend of mine observed that rot-gut vodka can be made into a "high-grade" product via passage though a Brita water filter. He used "Skol" vodka ($4/L rot-gut) and produced something reminiscent of Stolichnaya (or so he said); it was thus called "Skoli".

Cheers,

O3

[Edited on 10-9-2009 by Ozone]




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[*] posted on 11-9-2009 at 14:38


Thanks for that.

both columns are water cooled. I run the water into the condenser column, bottom first, and then into the refractionating column second (again bottom up) this gives me good controll over vapour out temp based on water flow rather than boiler heating temp.

The Graham cooler is angled at about 30 deg. and creates some backward preasure, and occillating flow within the system which influences the purging of the distilled alcohol, which creates a slow system that is contingent on the temp cycle of the boiler which runs at about +/- 15 deg of the target temp.

I'm looking to speed things up, but at the same time, not reduce the still efficiency. HTEP hasn't been calculateddue to the symetrical bulbing of the Allihn Column and the randomness of the s/s packing. But I estimate about 80% recovery on an initial run.

I've read about alcohol stripping from solvent (iso-propyl), but noot really understood it... it's been a long time since I was in the lab) recovery using a GAC packed column, hence my reservations, but also curiosity, with regard to this particular application.

=================================

Polishing refers to the removal of deliterious flavours and contaminant to produce a smoothe tasting alcohol. Basically what it means is passing distillate through a packed column of activated carbon to remove various esters, aldehydes and other "non-tasty" compounds, to create a smooth tasting beverage.

Excessive use of such filtration removes colour and beneficial favours, resulting in the production of a pure spirit, which is not always a beneficial result (consider schnapps, whisky, rum, schlovichic etc.) however, it's a definite requirement for vodka.

========================

Thanks Oxone,

I really appreciate the insight. It's got me thinking... again. :-)

===========================

[edited by Ramiel - Doooon't triiiiple pooooost]

[Edited on 12-9-2009 by Ramiel]
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[*] posted on 15-9-2009 at 16:05


I would filter after the distillate has cooled. Just because if it's passed through the carbon while still warm some of the impurities might not adsorb as well to the carbon. This is all speculation though.

Try it both ways and find out which makes the better product.
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[*] posted on 18-9-2009 at 06:36


Quote: Originally posted by kclo4  
Filter to polish the distillate?
What do you mean?


Bootlegging jargon!!

I couldn't stop smiling when i read your your post Chinawhite (incidentally isn't that a grade of heroin??), i run a small distillery that 'polishes shit', a very ungracious description given by my electrician once.
We have a huge glut of non-premium red wine in Australia and i use this as a source of alcohol, stripping the ethanol initially under vacuum, then redistilling with a little more panache.
Ozone is correct is spelling out the optimum temperatures for the charcoal. I use a column packed with carbon, however run the ethanol through from bottom to top using only the slightest height differential between feed and outlet to minimise the gravity fed flow. Running it bottom to top solves many potential issues Ozone describes for carbon columns as well as not aggregating the fines from the charcoal at the bottom of the column.
Graham condensers are pretty inefficient, especially given much of your cooling water is used to cool the atmosphere (ie the outside of the condenser). Pardon me if it seems patronising, but i have seen many setups where the cooling water flow was concurrent to the vapour flow to now assume its not general knowledge that countercurrent flow is thoroughly more efficient, especially if your intention is to warm the column with the condenser water outflow.
I am very concerned with your two liter round bottom however, as you will not be able to distill enough, even if running 24/7. A decent consumer of alcohol (not an alcoholic, they are indecent consumers) could likely sit him/herself at the end of the condenser and not become happy intoxicated for quite a while. This is a problem you will need to address.




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cool.gif posted on 18-9-2009 at 06:53


Quote: Originally posted by Panache  

We have a huge glut of non-premium red wine in Australia and i use this as a source of alcohol, stripping the ethanol initially under vacuum, then redistilling with a little morepanache


You would think that buying industrial ethanol would be much cheaper than consumer-grade wine. But then again, thek value of a good old flagon of Coolabah cannot be beat!

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[*] posted on 18-9-2009 at 07:56


Quote: Originally posted by Formula409  
Quote: Originally posted by Panache  

We have a huge glut of non-premium red wine in Australia and i use this as a source of alcohol, stripping the ethanol initially under vacuum, then redistilling with a little morepanache


You would think that buying industrial ethanol would be much cheaper than consumer-grade wine. But then again, thek value of a good old flagon of Coolabah cannot be beat!

Formula409


Ah!!! Yes you would think so and if everyone did i couldn't do what i do and that would bad oh so bad for meeeee!

i prefer Fruitylexia myself, has that feeling of tropics in every crisp sweet drop.




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[*] posted on 20-9-2009 at 22:17


sorry Ramiel, my mouse tends to stutter.

Lol Panache. Your comments certanly made me smile. the Chinawhite reference is tongue in cheek, but here it comes from being a long term expat in China. (now I'm based in Vietnam).

Thanks for the insight on the columns and the charcoal. I don't particularly like the way the Graham column works, hence the interest in going over to the Allihn columns totally.

Noted (thnx Hydro Carbon) about filtering after the distillate has cooled. Panache, I don't quite follow your description of feeding the distilate up through the bottom of the carbon column - wouldn't this create an increasing backward/resistive preasure on the rest of the distillation unit, hence reducing throughput?

The condenser (Graham) column is set up in counter-current arrangement.
The fractionating (Allihn) column is set up in concurrent arrangement.

Thus, as you rightly point out, colling efficiency is best achieved via counter corrent flow, however I'm not trying to "cool" the fractionating column, I'm trying to obtain a more consistent temperature gradient through the column compared with running it without water. When the vertical Allihn condenser column is set up in counter current arrangement, water does not flow evenly over the bulbed inner column. When set up concurrently, the entire column fills with water. Upper column temperature is then controlled by the rate of flow of the cooling water.

As for the thirsty consumers at the end of the coil, wellI guess part of it all depends on the initial alcohol content of the mixture being distilled. 5% v/v in 2 lt is only 100ml of ethanol (plus a bit of watering down due to column efficiency), and if that takes more than 2 hrs to distill, then you're right it's not going to be a very useful or efficient output. However at 18% v/v then two to three batches will produce around 1 lt of ethanol (80% in water) which can be then diluted to 40% v/v. which should give those parched and ravenous consumers a inner happy glow:after all, a man is not a camel. ;-)

[Edited on 2009-9-21 by chinawhite]
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[*] posted on 21-9-2009 at 00:30


Quote: Originally posted by Panache  
(cut)
We have a huge glut of non-premium red wine in Australia and i use this as a source of alcohol, stripping the ethanol initially under vacuum, then redistilling with a little more panache.(cut)
You should drink more of the stuff, then - it is supposed to be good for you.
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[*] posted on 23-9-2009 at 20:47


Quote: Originally posted by chinawhite  
Panache, I don't quite follow your description of feeding the distilate up through the bottom of the carbon column - wouldn't this create an increasing backward/resistive preasure on the rest of the distillation unit, hence reducing throughput?

[Edited on 2009-9-21 by chinawhite]


Sry yes of course this would, i however don't don't use the carbon directly off the still, i accumulate then run it separately. Too many bits need perfect optimising otherwise.




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[*] posted on 24-9-2009 at 17:19


Quote: Originally posted by JohnWW  
Quote: Originally posted by Panache  
(cut)
We have a huge glut of non-premium red wine in Australia and i use this as a source of alcohol, stripping the ethanol initially under vacuum, then redistilling with a little more panache.(cut)
You should drink more of the stuff, then - it is supposed to be good for you.


The stripped ethanol? :P




“If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search.
I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor.”
-Tesla
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