Still with 60″ packed Reflux column in operation
In previous articles 10.19 190 Proof Ethanol from Scratch, and article 15.8 Ethanol Fractionating Still, I discus how to produce 190 proof Ethanol, the difference being that the latter uses a reflux column to achieve 95% 190 proof concentration, while the former uses multiple runs in a vacuum pot still and mol sieve desiccant to achieve that end.
Underneath the towels, my test still is composed of a 6” X 12” boiling pot, with 5’ of 2” sanitary tubing stuffed with stainless steel ribbon from commercial pot scrubbers.
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/Vacuum-still-767x1024.webp?resize=767%2C1024&ssl=1)
Vacuum still assembly with 36” column showing bead bath heating
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Pot scrubber column stuffing from Hong’s Restaurant Suply
The boiling pot sits in a commercial electric soup pot full of aluminum beads supplied by Cascade Sciences, and there is a thermocouple in the boiling pot attached to a PID for heat control, and a thermocouple in the column head to determine the boiling point of the fraction currently in the column head.
The thermocouples were custom 1/8” Type J made by Wilcon Industries and inserted through 1/8” Swagelok compression fittings, that I through drilled so the thermocouple could pass all the way through.
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/column-head-1024x871.webp?resize=1024%2C871&ssl=1)
Column head with thermocouple and compound pressure gauge
I insulated the column with 1” thick closed cell foam 2 1/8” pipe insulation and all hoses are 3/8” 304 stainless steel over braided PTFE with #6 JIC connectors.
For a condenser I used a 10 pass single row copper tube heat exchanger with aluminum fins and added a blower from another double row heat exchanger.
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/Air-heat-exchanger-1024x694.webp?resize=1024%2C694&ssl=1)
3/8” 10 pass single row copper vapor to air heat exchanger using Derale components
For a collection jar, I used a thumper lid from Nor Cal Brewing Solutions. It is set up with a connection to the test sled vacuum pump, so the system can also be run under -23” Hg vacuum as a vacuum still.
I will be running vacuum still experiment for comparison once I establish a baseline.
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/Collection-jar-2-779x1024.webp?resize=779%2C1024&ssl=1)
Thumper lid attachment from Nor Cal Brewing Solutions
For my first run, I diluted 190 proof Ethanol 50/50 with water, to produce about a 95 proof and put it through the still with a 2” X 36” reflux column in one pass. After it cooled down, the 36” column produced 185 proof ethanol, so I added another 24” of packed reflux column to see what that would produce.
At 26C/78.8F a single pass measured 195 proof, which when adjusted for temperature above 16C/60F comes out 190 proof.
Oops, New Reflux Still Column Sizing Insights!
Sooooo, I was so elated with achieving my 190 proof azeotropic balance goal with my small still, that I failed to consider all the variables using a larger boiling pot.
Sometimes experiments verify and support pet hypothesis, and sometimes they fly in the face of them for obvious reasons, which I failed to adequately consider.
In this case I attached the same 2” X 60” packed reflux column to the 12” X 12” pot, vis a vis the 6” X 6” still base and expected similar results, despite the 4X difference in surface boiling area producing vapors.
As a result, I only achieved 180 proof in a single pass, demonstrating that I need more refluxing mass cooling down the vapors, so that only the lowest boiling point reach the column head.
I again packed my boiling pot in aluminum beads from Cascade Sciences for even heating, but this time used a 14” baking pan sitting on a Chemorec 2 hot plate, instead of an electric soup pot.
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/Large-pot-in-beads-1024x902.webp?resize=1024%2C902&ssl=1)
Large Pot in Bead Bath
![](https://i0.wp.com/graywolfslair.com/wp-content/uploads/2023/04/Large-reflux-still-1-532x1024.webp?resize=532%2C1024&ssl=1)
Large Pot In Operation Insulated and Wrapped
The run was smooth and uneventful, but demonstrated the need for more reflux area, which I don’t have room for in my kitchen, so will have to wait until I can move back in my garage lab/workshop or go to a larger diameter column.
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