44" reflux column too tall for 2" pipe on 8 gallon boiler?

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Hexadecimal
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44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Hexadecimal »

I have an 8 gallon boiler and just got a new reflux column. The arm to the condenser is at 44" from the top of the boiler.

The setup is as follows:

1. 18" SS tube
2. 12" copper tube
3. sight glass (ceramic beads / copper mesh go here)
4. Dephlem
5. condenser arm attachment

That's pushing the 20:1 ratio for column height on a 2" setup. I'm currently using propane which shouldn't be an issue to heat it up, but I'm wondering if I should worry about trying to get it down a little shorter.
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still_stirrin
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by still_stirrin »

Too tall??

For a reflux stillhead, it is the length of the “packed section” that affects purity. You can have a towering 80” riser above the boiler and it won’t increase purity. Reflux only occurs in the packing as falling (condensed) liquid is reheated by rising hot vapors and the heat is exchanged in the packing. It is the repeated boiling/condensing/reboiling cycles (reflux) that separates the volatile constituents from the non-volatiles (water).

As for your power source (propane burner), it generates the vapor in the boiler, so more heat input —> more vapor production. And with more vapor production, the rising vapors will be faster flowing (mass flow, right?). So, as the heat input affects the vapor speed, it can entrain more liquid into the vapor stream and cause smearing (in a potstill).

But in a reflux column, the vapors are condensed by the reflux condenser and sent back down the column, creating reflux (heat transfer). This will increase the “reflux ratio” and the will increase the purity of the product at the spout.

So, in conclusion, your 44” measurement from the top of the boiler to the top of your stillhead is NOT TOO TALL, depending on how it is configured and how you intend to run it. Certainly it IS TOO TALL for the purpose of a potstill, that is, if your target spirit is a whiskey, rum, or a brandy. If you want a clean neutral spirit (vodka), then the tall tower will work for you.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by howie »

should be ok for reflux.
my 2" is 55"/1400mm including the column and shotgun.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by greggn »

Hexadecimal wrote: Wed Aug 04, 2021 6:50 am 3. sight glass (ceramic beads / copper mesh go here)

Are you saying that you're only packing the sight glass ? Nothing in the spools beneath it ?

If so, then you're not going to get much reflux and all that column height goes to waste.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Hexadecimal »

Shoot, got it. I wasn't thinking about the packing correctly. I'll just move the mesh TC gasket to the bottom and fill the pipes with more copper mesh and packing.

Thanks everyone!
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by still_stirrin »

Hexadecimal wrote: Wed Aug 04, 2021 11:29 am….I'll just move the mesh TC gasket to the bottom and fill the pipes with more copper mesh and packing…
CAUTION! Using one of the T/C gaskets with included “mesh” can cause flooding in the column, or worse … a “choked flow” resulting in boiler pressure build up!

If you’re using a molded T/C gasket with a mesh, make sure it is very, very porous, basically a wire grid only.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by howie »

Hexadecimal wrote: Wed Aug 04, 2021 11:29 am Shoot, got it. I wasn't thinking about the packing correctly. I'll just move the mesh TC gasket to the bottom and fill the pipes with more copper mesh and packing.

Thanks everyone!
i've not tried any other packing in my short journey.......
but in my 1100mm of S/S column, there is 400mm of copper mesh and 700mm of S/S scrubbies.
the mesh is a tightish fit (at the top of the column) and the scrubbies packed underneath.
nothing has ever fallen out yet, so i have no need of a mesh gasket.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Yummyrum »

Also agree . Packing will hold it self in place . Holders are not needed and only cause problems .
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Hexadecimal »

still_stirrin wrote: Wed Aug 04, 2021 12:27 pm
Hexadecimal wrote: Wed Aug 04, 2021 11:29 am….I'll just move the mesh TC gasket to the bottom and fill the pipes with more copper mesh and packing…
CAUTION! Using one of the T/C gaskets with included “mesh” can cause flooding in the column, or worse … a “choked flow” resulting in boiler pressure build up!

If you’re using a molded T/C gasket with a mesh, make sure it is very, very porous, basically a wire grid only.
ss
I got the #10 (2mm) mesh so there shouldn't be any issue with flooding. I only went this route because i have had some mesh fall into the boiler before in an older pot still. I was just worried about that happening again.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by still_stirrin »

Hexadecimal wrote: Thu Aug 05, 2021 5:21 amI got the #10 (2mm) mesh so there shouldn't be any issue with flooding. I only went this route because i have had some mesh fall into the boiler before in an older pot still. I was just worried about that happening again.
Well, if you experience flooding, the screen is likely the cause. Some distillers have to “learn the hard way”. And some will defend their choices over and over, hoping for different results. We’ll see….
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Deplorable »

A wire grid soldered from 10-12 gage copper wire is all you need to hold the scrubbies or copper mesh in place.
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by jonnys_spirit »

005C9E3A-AF12-49A8-A2BE-54E3A49D86D7.jpeg
If you experience flooding issues with #10 mesh and still enjoy some removable support integrated into a ptfe gasket there’s a tool that’ll turn the flooders frown upside down.

Cheers!
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Re: 44" reflux column too tall for 2" pipe on 8 gallon boiler?

Post by Yummyrum »

Hexadecimal wrote: Thu Aug 05, 2021 5:21 am I got the #10 (2mm) mesh so there shouldn't be any issue with flooding.
Time will tell , but sounds to me like it will act more like a sieve plate with no down comer . :wink:
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