Reflux ratios

Stillhead · Post by **Stillhead** » Wed Dec 20, 2006 11:14 am

While doing a stripping run, I took a few measurements while into the hearts.

Using a 1500W element, 0% reflux, and a cold condenser, I collected 43mL/min

One tenth of this would be 4.3mL a minute, which is where I would assume I need to be to make neutral spirt.

On the homedistiller site, the calculator says:

If you have an 1500W heating element, and you are collecting the distillate at 4.3mL/min and at 94%

the distillate flowrate would be 119.9mL per minute if you were to reflux none of it, but you presently have a Reflux ratio of 27.9.

Seems strange. Not to get too philisophical, but ...What am I doing here?

Bryan.

Post by **Husker** » Wed Dec 20, 2006 11:20 am

Not taking into account the heat loss. You are not getting 1500W, but probably closer to 1150W. Insulate your boiler (and the column), and see if your take off rate (with no reflux), does not increase quite a bit.

H.

Edit: I just did a reflux calculation with 48L of 14%, 0 reflux, a 1.5" column, 1500W. It ended up listing 46.1 mL / minute, so I am not sure what calculator you are using, or if it accurately is showing what you are expecting.

Stillhead · Post by **Stillhead** » Wed Dec 20, 2006 11:30 am

I used the calculator uder the link "Using a Reflux Still."

My boiler is insulated. So is my column. The calculation you did seems accurate to what I have actually happening on my system.

Post by **Husker** » Wed Dec 20, 2006 11:53 am

Go to this page:

http://homedistiller.org/calcs/reflux_calc" onclick="window.open(this.href);return false;" rel="nofollow (it is under Theory / Interactive Design Calculations / Reflux Still Sizing and Purity)

Enter:

Vol: 48L (change to your values).

TimeStep: 10min (note you will have to divide by 10 to get proper results).

Alc Content: 14% (change to whatever you are expecting by the time you hit your hearts). I used 14%, since I assumed that you had already stripped out some ethanol, since you said you were well into the hearts.

Init temp: 78 (not worried about heatup, so simply set to this value).

Wattages: 1500 (put both to that).

Height of packing: 1.1 (I assume 1.1M but change to what yours is).

Column Diam: .038m (about 1.5"), change to 51 if you have a 2" column.

Reflux Ratio: Set to 0.001 (Tony's web site can not handle 0 correctly) To test that the results are actually correct, set RR to 1, and recompute, and see that the output is 1/2 of what we get here.

-------------------------------------

Results of what I did above: 10 minutes, 457mL or about 45.7 mL / min.

H.

Stillhead · Post by **Stillhead** » Wed Dec 20, 2006 2:23 pm

49mL was the value it spit out for me. My measured value is 43mL.

I suppose that my still is up around 80% efficiency.

It just takes so long when I have to collect around 7L at a reflux ratio giving me 4.3mL/min.

Like 27 hours theoretically if I didn't change the ratio when in the hearts.

I took the element out and cleaned the baked on crap. This should give me a better boil up rate.

Stillhead · Post by **Stillhead** » Wed Dec 20, 2006 2:32 pm

Incidentally,

I counted 226 drops in 10mL (graduated cylinder)(4x)
This took 3:42 (bout a drop/sec)

I measured 43mL/min with 0reflux, and I want a 1/10reflux ratio.

4.3mL/min x 22.6 drops/mL
= 97 drops/min
=16 drops/10sec

speedfreaksteve · Post by **speedfreaksteve** » Thu Dec 21, 2006 2:20 am

Do you really need a 10 reflux ratio after a strip run to get good neutral spirit? I thought it would be abit lower than that like 6 or something.

If I keep the temps low on my potstill I can get as high as 77% on a first run for alot of it with 14% abv.

Stillhead · Post by **Stillhead** » Thu Dec 21, 2006 9:03 am

I don't use any reflux on my strip runs. I am talking about refining to a neutral spirit.

speedfreaksteve · Post by **speedfreaksteve** » Thu Dec 21, 2006 11:28 am

Maybe you misinterpreted what I was trying to say.

Assuming you already did a strip run, would your spirit run really need a RR that high? I'm not that experienced making neutral spirit, but wouldn't a RR of 6 probably be enough?

Stillhead · Post by **Stillhead** » Thu Dec 21, 2006 12:21 pm

Yeah probably. I usually use 6 when I am into the hearts.

Enlikil · Post by **Enlikil** » Fri Dec 29, 2006 11:05 pm

When i do a strippin run i pull off an 800 ml jar in about 7 minutes.
about half way through i gotta turn the temp down or i will start blowing brown wash up and out LOL. heheh once i turn it down it clears right back up.. hehehe..

Takes me about 2 hours from start to finish on a striuppin run of 5 gals.
THen... About 2-4 more hours the second run through..
I have found without a doubt that a good wash is key.