Extension to the ultra pure reflux column

[crow]

G'day well I screwed the extension I made for the pot on to my reflux column so I could attach it to a keg works ok but I'm use to pulling 95+ ABV and now am getting 87 to 88 ABV would it be the extra column length causing that or the much colder weather , and why . I intend to make an extension just for the reflux but if the length of it is going to affect the performance I'll need to make it pretty short

[Kimbo]

How much packing have you got in the column Crow?
can you get 100% reflux?

[crow]

none in the extension the top bit is packed about 4" or so up the original column to just under the take off it was fine until I put the extension keg connector piece on . I can't see how that would make any difference but then i don't know a whole lot about what can affect vapor refluxing either

[Kimbo]

Try packing the rest of it, then let it equalize (100% reflux)for a half hour (once at temp) then slowly bleed the distillate out.
see if that works.
failing that, remove the extension ;-)

[crow]

Cheer Kimbo I'll have to try it next run I'm almost through it now . In fact just shot out to see if the tails had started . I read some posts about equalibreim or something like that ,went over my head a bit I'm afraid . i really need to sit down with someone who knows all this stuff I think to get it to sink in fully . I think I can avoid all this drama i got ATM by making a shorter connector or from what I understand maybe insulating it . Trouble with doing things with out knowing fully why ya doing them is when it doesn't work your up shit creek hey

[MacStill]

Pack it and insulate all the column below the take off point :handgestures-thumbupleft:

[crow]

Ok I'll have to pull them out for pot stilling though won't I or won't it make any difference for that

[eminiM]

Ok I'll have to pull them out for pot stilling though won't I or won't it make any difference for that

Packing will have very little influence without reflux so in potstill mode you should be fine just leaving the packing in.

[crow]

Cheers I'll do that then :handgestures-thumbupleft: get me out of trouble until I build a shorter adapter piece PS I ended up only getting a tad over 70 %

[grumpthehermit]

SO is there merit in extending the column on one of these stills ???

I was thinking about this for mine but reading Croweaters experience I am thinking maybe not ???

Just wondering.

Cheers
GTH

[crow]

SO is there merit in extending the column on one of these stills ???

I was thinking about this for mine but reading Croweaters experience I am thinking maybe not ???

Just wondering.

Cheers
GTH

I don't know if I took the advise I was given it would probably be fine . No one seems to be able to tell me the physic's behind whats going on with the vapor in the column that would cause the refluxing to change with the extension :-?? . I think this little still is pretty damn cool as is and I only changed it to put it on the keg but I'll build a connector just for the U.P.still and make it much shorter say 3 or 4 "

[stilly_bugger]

Croweater, I did a very similar thing with an Ultra Pure column that I have. I added 1000mm of 50mm copper column extension and, at first, joined it with the same brass fittings that you've used.

Before I extended the column I was pulling around 92-94%. After I extended it I began pulling a consistent 94-95%. While the percentage increase isn't that much more, the separation of heads from main run is much more distinct, especially if I let the column reach equilibrium before I start taking off product -- that is, if I wait at least 30 minutes between when the top thermometer gets up to temp and when I open up the take-off valve (from memory the instructions that come with the Ultra Pure tell you to wait 10 minutes). Once I've taken the heads off I also shut off the take off for another 15 minutes to let the column reach equilibrium again before collecting the main run.

boka_extended.jpg

The benefit of the extension comes when you fill it with packing. By filling your extension with packing you radically increase the amount of times the vapour condenses and re-evapourates ('theoretical plates') before it gets to the top of the column and condenses on your coil condensor and either refluxes back into the column or is taken off as product. So fill your extension. I used stainless steal scrubbers from Woolworths. These ones:

Untitled-2.jpg

Don't pack them in too tight.

I've been using the extension for about six months and it works great. I ended up ditching the brass fitting and soft soldering the extension to the original column with a 2" copper coupler. I also insulated the whole column.

As for why your column is producing lower percentages with the extension than without, that's got me stumped. I you didn't pull the packing out of the original column, then there's no reason for your percentages to change given that you hadn't packed the extension. However, if you pulled out your packing and repacked it (which it sounds like you might have when you mention that the packing is 4 inches from the bottom of the original column) then the lower percentages might have something to do with how you've repacked it. Packing too tight is no good.

Like you said, these are pretty good columns as is. But where's the fun in leaving the thing as is? You've gotta pull these things to pieces and try to make improvements. Sometimes they work straight up; sometimes not. Keep at it. There's no reason why you shouldn't have it pulling 95% in no time.

Best,

Stilly.

[eminiM]

Don't pack them in too tight.

I'm really questioning that advice since working with SPP which is far denser and packs much tighter than scrubbers. Wish I had time to experiment immediately but it'll likely be late this year before I do. I intend to spear scrubbers on a threaded rod and cinch them down with washers at different densities before inserting into the column.
Goes against conventional advice but I've never seen results for that type of experimentation anywhere.

[stilly_bugger]

Me neither. I'm just going off the advice in Nixon & McCaw's The Compleat Distiller (p. 90):

Scrubbers

We believe that metal scrubbers are the best packing material to use in a distillation column. However, people have more problems handling scrubbers than with any other part of their still! More often than not, scrubbers are taken straight out of the packet and pushed directly into the column. This is the easiest way to ensure that they're packed too tightly. Since they have a rough surface, the scrubbers tend to grip the sides of the column. Shoving them into a column is rather like trying to push an unwilling cat through a narrow hole − it tends to resist!

We've found that the best procedure is to pull the scrubber out into a loose cylinder, which should slip easily into the column. Remember, we want a lot of airspace inside the scrubber so vapor can get through easily. If you still have trouble with them, you can cut them into smaller pieces that will slip easily into the column without bunching up. After filling the column with scrubbers, you should be able to blow through it relatively easily. If you feel resistance, you have packed the column too tightly.

Another test for proper packing is the ability to get the scrubbers back out. In a properly packed column, the scrubbers will remain in their place, but can be easily pushed out with a large dowel or a pipe that fits inside of the column. This same dowel or pipe can be used to gently push scrubbers down into the column when packing it.

Initially I had my column and column extension packed pretty tight. After reading this I unpacked it and repacked it a little looser. I don't know for sure, but I seemed to get better results. I should say that I insulated the column at the same time, so that may be the cause.

P.S. I'm still trying to work out what SPP is. :think:

[eminiM]

Me neither. I'm just going off the advice in Nixon & McCaw's The Compleat Distiller (p. 90):
P.S. I'm still trying to work out what SPP is. :think:

Spiral Prismatic Packing...........likey 4 or 5 times denser than scrubbers and has a much lower hetp value. I think it's a combination of packing density and weight which allows for better stability.
Insulation on a column is critical for consistent results. An uninsulated column is subject to outside influences.

[crow]

Hi guys , No I didn't alter the packing at all and like I said it always got around 95.4 give or take one or two fractions . The only other variable was the burner which was vastly inadequate I haven't tried packing the extension yet as I was going to make another column anyway but my plumber hasn't turned up yet :-x (I don't have a ridged tree expander) so I might have to run these neutral washes with the other extension anyway , besides I told Grumpthehermit I'll pack and insulate it to see if it makes a difference as he was looking to do the same thing with his . So I'll try it early next week and post how it goes , I can see how it wouldn't improve it without packing but as to why it made it worst I'm not sure unless it needed much more time to reach an equilibrium than I gave it EDIT @Stilly just wondering whats with the lower thermo reading , as in what information do you get from the lower reading different from the higher reading and how does it benefit . easy enough for me to put one in if there's a need for it

[stilly_bugger]

@Stilly just wondering whats with the lower thermo reading , as in what information do you get from the lower reading different from the higher reading and how does it benefit . easy enough for me to put one in if there's a need for it

The thermometer port was already in the piece of 1m x 2" copper that I had (an old reflux column), so I just left it in there. I was going to take it out, but I thought I'd try to see if there was any benefit in taking two temps. The lower thermometer just ended up letting me know when the temperature change was on its way up the column. Anyway, I didn't find that I really needed the two temp readings. All you really need is the temp reading that your Ultra Pure head already gives you.

And I hope you get that thing back to its old self,

Stilly.

[grumpthehermit]

Hey Crow,

Hope you get round to packing the extension and getting another run out of it.

I'm very interested to see how you go with it.

Cheers
GTH

[stilly_bugger]

Spiral Prismatic Packing...........likey 4 or 5 times denser than scrubbers and has a much lower hetp value. I think it's a combination of packing density and weight which allows for better stability.

Comprende. Just read the SPP thread here and on Artisan. More mass => better stability makes sense. :handgestures-thumbupleft:

[crow]

Okay I packed and insulated the extension column and got between 94.5 and 95% . The still operated a bit different than it previously has in that the heads were much more compressed also tails started at a much higher ABV than they ever have before (90+ ABV) and most the tails came out at 70% . The down side was that the tails slowed to a painfully slow pace while still at the 70% mark . Once it started to drop it the ABV dropped fairly quickly down to 40% and at that point I shut it down . Here's the strange thing the last jar took 3 times as long or more than any other and yet most of it came out at above 60% . Anyway I,m reasonably happy with the result