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An experiment with CM/LM and a DASH-2



  • Test one is finished. I used a wash of approx. 20% ABV.

    top     = 73.3°C (top temp at U bend)
    plate 6 = 75.0°C
    plate 5 = 76.0°C
    plate 4 = 76.2°C
    plate 3 = 76.3°C
    plate 2 = 77.7°C
    plate 1 = 79.6°C

    ABV per plate with Temp when pulling from each plate individually:

    plate 6 = 89% ABV = 74.8°C
    plate 5 = 88% ABV = 75.9°C
    plate 4 = 86% ABV = 75.6°C
    plate 3 = 82% ABV = 75.4°C
    plate 2 = 76% ABV = 76.8°C
    plate 1 = 65% ABV = 77.8°C

    Product temp 59.8°F = 15.4°C

    Not sure how accurate this is as the thermos are not exactly the best but is a result that is worth looking at.
    I will be adding the mod to be bale to return to boiler and thus disable plates. Should be able to start shortly and will update when finished.

  • At what flow rate are you pulling from the plates? If you take a significant portion of the reluxing liquid, this will be a significant perturbation to the column. Starting from the system in full reflux, did you notice that the plate's individual change a lot when you start pulling?

  • Take off rate was approx. 2 to 3 L/hr and there was enough reflux to keep all the plates below happy and bubbling away to the extend that I do not believe it was upsetting the column at all.

    I have replaced the 3" x12" TC section with one that I modified so I can return to the boiler and play with plate disabling. I will have some videos at the end of the day.

    Here it is with the modified TC section


    I will start this new test shrtly and update as I can

    test day 2 004.JPG
    600 x 800 - 78K
  • This last test was not good. Seems vapor coming up from the boiler wanted to follow the path of least resistance and wanted to go up the collection tube. :-S No matter what I tried the top plate stayed loaded and abv stayed up hi near 90 :-w Maybe a case of a lot of passive reflux going on, I really do not know.

    So I switched back to the other collection method, and now pulling 80 ABV out of plate 2 at 76.3C and product temp at 62F. Win some, lose some.

    I am very happy with the overall results. Next time will attempt to run a wash at 10% and pull from plate 2 or 3 at 80 ABV.

  • A short video of the second day of testing.

  • It has been brought up to my attention that perhaps I need to run the return back into the boiler below the fluid level for a vapor lock. Will figure out something and run more tests.

  • Yes return below liquid level.

    Are your vapor temps corresponding with abvs being collected according to the chart ?

    StillDragon North America - Your StillDragon® Distributor for North America

  • @Myles has the charts for different washes up to 45 ABV. Perhaps he can look at the chart for 19 ABV and compare the numbers for us. I was going for a 20 ABV wash, the boiling temp came in at 192F which is consistent with an approx. charge of 19 ABV.

  • edited February 2015

    Another test run results from this morning.

    15% ABV wash

    plate 6 = 74.5°C
    plate 5 = 75.4°C
    plate 4 = 75.3°C
    plate 3 = 75.2°C
    plate 2 = 76.6°C
    plate 1 = 78.8°C

    Was able to pull from plate 2 at 80% ABV and 76.6°C

  • Ok all the stats I have are from a simulation program and they are all for a column that has stabilized. In every one the temperature of the top plate and the reflux condenser is 78.2 deg C.

    With a 15% wash you should be getting 81.9 deg C on the first plate. What this suggests to me is that (compared to the theoretical ideal) you may be overcooling. What is the temperature setpoint on your dephlegmator coolant?

  • Just a perspective from someone that lives and breaths control and temps every day - before blaming the process - check the accuracy of your measurements. Those low cost 2 wire thermometers from my experience are for guide only.

  • edited February 2015

    Example of differences in NTC probe readings - Thermometer is a Smith-BioLab 200mm.
    2 x SDs, other LHBS (6 x SD price)


    800 x 600 - 80K
  • edited February 2015

    Thanks @Myles and @dellae . I do not have a way to set the Deph coolant temp. Basically stabilized in full reflux with nothing coming out past the Deph. and then collecting from a plate as a liquid. I might need to tune the reflux down some as I recall the cooling water temp coming out of the Deph. was not much above 35 or 40C and it is usually closer to 50 when collecting in normal mode.

    These thermos are only temporary and will be replaced with some Vernier ones soon. It is still very nice to see the temp gradient up and down the column. I look forward to more test with more accurate equipment.

  • The thermometers have been replaced with Vernier equipment and software and I can now test with better accuracy.

    This is a summary of a test run with 10% wash. Boiler is temp 1 then plates 1 thru 6 are temps 2 thru 7 and above the Deph. is temp 8. I added some notes to the chart and will continue to update as I go.


    I also reconfigured the still by removing the sight tower and locating the probe above the Deph on the very top of the "U" bend. I will be doing another test soon, and will be comparing the temps with what I can draw from each plate.

    vernier run 2 001.jpg
    800 x 758 - 90K
  • Really cool. Easy to understand what's going on and when.

  • +1 @captainshooch!

    I wish I would have the same equipment available...

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