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Multi Column Drains

edited February 2015 in General

I plan to use two columns on my boiler.
First column a 6 plate 4" CD with dephleg feeding out and down into the bottom of the second column a 750mm high 4" CD packed section. Most multi columns sit on a bench or are separate from the boiler and need a drain back to the boiler otherwise column two will flood. If the bottom of column two is capped and does not drain back to the boiler or column one do you think the boiler heat would be enough to prevent flooding.


  • No, it will not @what. It cannot help but to flood column two.
    The second column will always produce reflux, passive or active, that will work its way to the bottom of the column. And the more you run with reflux (you have to have reflux) then the more liquid will accumulate at the bottom.
    The big debate is where to drain that back to and in my little mind it would be somewhere, ideally, in the middle of column one - much as a continuous stripper still gets its' beer injected into the column.
    But feeding the drain from column2 into the bottom of column1 is certainly something to take a good, long look at. One of the biggest problems is that column1 also needs to drain somewhere and that's got to be back to the boiler unless something like another, separate boiler is in the mix.

    Easy answer is back to the boiler or it starts to get exponentially complex.

  • edited February 2015

    You could maybe have a look at how @meatheadinc has done it? I think though that he has the second column with it's own power source.

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  • Which is 100% different than capping off the bottom of the column?

  • @what you need a drain. It is possible to drain the column to a storage container, but the conventional approach is column 2 into column 1, and column 1 into boiler.

  • edited February 2015

    @punkin said: You could maybe have a look at how meatheadinc has done it? I think though that he has the second column with it's own power source.

    pictures posted here are a single boiler and heat source mounted under the first column .

    I have used a second boiler/power source - second column mounted on a second smaller boiler to catch and re boil reflux, and found that balancing power to the second boiler was extremely fiddly, either flash boil and leave the boiler dry or start to over fill. ( second column has 90+abv) if trying a second heat source keep in mind the higher abv of the column- very little power is required in the second boiler

    I found the single boiler much easier to control, although I did require more power.

    Ideally I would like a humper thumper(inline parasitic boiler) on the first column for reflux return from column 2, although returning to the plates is working at the moment

  • edited February 2015


    Above image is second boiler. Vapour feeds in at the Tee and elbow on the left -from column 1. column 2 mounted above bubble tee to condenser.

    This setup allowed use without a reflux return line as you re- boiled the reflux in this second boiler. although fiddly it is another option- although proceed with caution

    I may revisit this design with boiler 2 as a powered thumper instead of a catch can

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  • Thanks guys I think I am starting to understand, looks like an extra plate under the CD on column one might be a good place to start for the drain from column two. Would it make a difference if column two has no dephleg and runs straight to the condenser? If the abv collecting at the bottom of column two is higher than both the boiler and column one it should as you say boil at a much lower temp, if that is the case than what about extending the bottom of the column down into the boiler to make use if the existing heat.

  • Column 2 is a packed column. If your column looses enough heat to generate natural reflux then you don't need a dephlegmator. However you are limiting your options if you go down this route.

    If your packed column gets hot enough to dry out, then your packing will do absolutely nothing. Remember the packing is just there to provide a surface for vapour liquid interaction to take place.

    No liquid means no re-distillation.

  • edited February 2015

    "What" is you boiler the black horizontal cylinder with 2or 3 4" mounts on top ?
    If so you may be able to use a solid copper plate and a tee to mount the second column on the boiler without a drain
    Post a pic
    If so you could try...
    Blank off the boiler on the spare port between a Tee triclamp connection ( like normal plated column but solid plate).
    use the Tee as the vapour feed with the second column on top. The second column will be feed high abv from column 1 and I would presume that there would be enough heat on the bottom plate provided by the blanked off boiler to drive the seconds column (Re boil reflux). although it may drive the second column to hard

    It would be a good idea to have a large volume at the bottom of the second column if testing this idea to allow for flooding

  • Thanks Myles it's too easy sometimes to get wrapped up in things and forget the basics. Meatheadinc Yes my boiler is the one you describe and the copper plate idea is basically what I was thinking, I did wonder about how hard column two would run, but thought I might be able to control it with either the volume of reflux from column one or some form of cooler/ dephleg on the bottom of the column.

  • @meatheadinc (and everyone else) have you gone through this thread?

  • Thanks for the link I hadn't seen it

  • @meatheadinc - I thought about doing exactly what you have there. Didn't go through with it. My thought though was that the second pot would have water in it that I would use a PID to maintain just below water boiling temp. The idea was the PID would regulate the heat as needed to drive any alcohol back out of the water. I'm not sure what it would have really done, and wasn't worth the work to test for me. But since you have it set up, maybe give it a shot? If you think the idea is at all sound...

  • Don't disregard the thumper option. It is the one I have picked for my own 4" dash.

    I will be modifying a 30 litre keg to act as the thumper and table mount for the dash. I have a 100 litre keg as my primary boiler. My only problem is that I keep looking at the plans for the copper boiler. I don't need it, but I do want it. ;)

  • so something like this?

    4 plates on the boiler, then to a thumper with 12 plates on it, put distilled water in the thumper, as long as you can keep plates loaded, you are set... (after, just add the thumper contents to the next batch...)

  • I wouldn't put anything in the thumper, it will charge when you start running with the overflow from the bottom plate. I would put a level indicator on it at first because dependent on your primary boiler, you won't know how full it will get till you try it.

    You may need an overflow - but you might not. I would be inclined to have it drain to storage for adding to the next run. If you are going to overflow to boiler then your thumper and boiler max fill levels need to be taken into account. Depends how much height you have available. Overflow to boiler is easier - if you have the head height available.

  • I think.a drain straight from the second column straight into the base of the boiler would work what. Regards to no dephleg on the second column, I've tried mine that way, 90% off the first column into the second with no coolant on the second produced 92ish%, both refluxing produced 94~95%.

  • @Myles said: I wouldn't put anything in the thumper

    The Moonshiners (TV-Show) have high proof booze in their thumper when they start, don't they? :-B

    We need an own THUMPER discussion, with pics, instructions and best practices. Who is qualified enough to give it a go?

    Computer, ping @Myles! :-h

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