If I wanted to build a vac still out of a keg I’m wondering what size condenser I’d need for it to make it run efficiently
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How cold can you get your condenser is a big part of that question
-20 auto chiller 5 ton ac hack plus a 2.5 ac hack or a keg full of dry ice and iso -76
Budget: run a copper coil through a bucket of dry ice and iso
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I wonder what the condenser surface area of a 50L rotovap is? That would be a good place to start for sizing a condenser. Though you can really never go too big, so I’d probably just go as big as I could afford so I can use it on a larger still later. Now that we’re talking about it, I’m wondering if I should just use the 5k I was going to put toward a 20L roto and just build my own Bain-Marie vacuum pot still. I’ll have to do some digging, but I’ve seen quite a few folks getting at least as fast of recovery as a roto if not faster with custom rigs. The hardest part seems to be agitation/stirring.
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I did a good bit of research and talked to a couple still producers (Mile High & ADE) before building my still. both of their vacuum still designs are basically the same, they use large jacketed reactors and short path style column with a 45-60* bend right at the top of the pot.
their stills are designed to be run in batch mode, they have a small water heater and a pump recirculating the water through the jacket portion.
The condenser size is related to the surface area of the evaporating liquid, vacuum level, heat input, and condenser temperature.
On the condenser I went overkill to a small degree in hopes of preventing the need for a cold trap and I got lucky. I use a dip tube in the collection vessel, the tubes in the condenser are packed with stainless steel wool. I run the condenser @ 0F without a cold trap, I have tested with a cold trap before my pump and had maybe a shot glass worth of ethanol over an eight hour recovery cycle.
There are definitely some things I would change on the evaporation side if I built my still a second time.
I built my still to run in a batch style, to me this is a lot of wasted energy, if I were to do it over I would have it run continuously. heating a smaller jacketed chamber, a 12" jacketed spool with one of @Rowan wiper setups & ferro fluid rotary feedthrough plumbed through the bottom endcap would be a good starting design. The feed could be introduced through the top endcap via small stainless tube with small orifice holes angled to spray a fine stream on the walls of the spool.
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How much more efficient do you think it would be this way? The spool instead of a keg. How long would the spool be?
Make it a long spool with lots of tubes in it…oh wait, that’s an FFE 
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What kind of budget is something like that? You got any threads up detailing it? I feel like when looking at some stills I don’t understand exactly how to use them for etoh recovery… I’ve used a rotovap plenty of times, but never a still for evaporation. I can see it’s basically got a boiling flask (large pot), a condenser, and a collection pot. So I’m assuming you use them the same way you use a rotovap? Chiller to condenser, vacuum hooked up to a port?
Exactly but
Must have relief valves or u will die
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Care to elaborate? I’ve just been a still billy even before the extraction days
Can you elaborate on that? Think I understand, but the word “die” being used I want to be sure 
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Like a valve to realse pressure build up if the still is not condenseing from a liquid to vapor to liquid the vapor would build and boom ur fuckn dead lol
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Take that “spool”, add tubes to make the evaporative equivalent of a shotgun condenser, and you’re starting to look just like an FFE.
Which is different from wiping the spool as @Rowan suggested
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Better then batch style pot still ? Fuck why is there always something new. Kinda like a new chick coming into town and my hot gf starts lookn ugly quick ha
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what speed are you able to recover off this now that you had it a while
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It says 20l hour on pic lol
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that was at the beginning without him tweaking i believe