Building a Vacuum still with boiling point @ 98°F

[siko]

Hi you all fellow builders
i am building for a second time in my life a distilling machine. it will be a low temp stills. hoping for a boiling point @97-101°F.
here are some pic of what i have done today
please if you have a good idea.... well i love to learn of others

here is a pic of the Extended beer keg with th drain, temp probe, and connector to 3kw heating element it is upside down ofc

Keg reddy with temp probe, drain, and 220v 3kw heating element at the bottom :)

with all the parts i need to assebly the column and build the condenser with the coil that i made,

my work bench with all my parts ready for welding

first i start on the condenser #1

3,1/2" pipe and 8mm tube coiled

better hold

look it is getting there

[emptyglass]

Have a look around for some vacuum stills on the site, it might save you a lot of trouble. Theres quite a few issues in building a vacuum still that you may not be aware of. Cuts are hard to do unless your equipment is set up for it, 3kw will be way too much without a controller, and a few other things.

[siko]

Have a look around for some vacuum stills on the site, it might save you a lot of trouble. Theres quite a few issues in building a vacuum still that you may not be aware of. Cuts are hard to do unless your equipment is set up for it, 3kw will be way too much without a controller, and a few other things.

yes i know been researching a lot and it is my second vacuum still that i build

I have a SSR relay 40amps, and pid controler

more update is coming soon

[shadylane]

Just a thought.
Heating vacuum still to 98f will be easier than at atmospheric pressure.
Cooling the vapors may be a little bit more difficult.
I don't know much about vacuum stills, but I do have a collapsed corny keg from an old experiment.

Edited: nice welding and build siko

[frozenthunderbolt]

interesting.
I'm contemplating a micro (circa 2-4L) Vac still build as i want to recover ethanol after making olive leaf extracts, but don't want to go over 60C max.

[skow69]

Hello siko. I'm glad to see you back on the forum.

You know this, but I will state it for the benefit of others. If you want your wash to boil around 100f you'll need a vacuum of 27-28 inHg, which equates to external pressure of 13-14 psi.

Looking at your first photo, it's impossible to scale, but that looks like a pretty long section of straight sidewall, i.e. no ribs for strength. You might want to run your specs through this calculator: http://www.gtssnc.com/index.php?option= ... 12&lang=en. Remember the collapse yield is inversely proportional to the diameter after some minimum length. I don't have a formula for that length, but I would guess something like 2 diameters.

Keep posting pics, man. I love to watch your progress.

Skol,
skow

[skow69]

Just a thought.
Heating vacuum still to 98f will be easier than at atmospheric pressure.
Cooling the vapors may be a little bit more difficult.

This is usually one of the first comments made in a discussion of vacuum distillation, that condensing will be a problem. I remember one guy who was convinced that a liebig couldn't possibly be efficient enough to do the job.

The thing is that you can't change the latent heat of vaporization, or liquefaction. So the amount of heat you have to add to change a boiling liquid into vapor is the same regardless of pressure. Likewise, the amount of heat you need to extract for it to condense doesn't change either, so the same condenser you use at atmosphere will do the same job under vacuum.

The limiting factor (for me, at least) is the pressure at which the product boils at room temp. I found, through experience, that point to be about 28 inHg with a 50% ABV output. Now I stay below 27. It's an odd thing to see your product boiling away in the collection vessel.