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Re: [Distillers] Vapor management versus reflux control

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  • homedistiller
    Johan, Your post is quite complex because you mention both, batch and continuous disitllation. With batch distillation, all the fractions will follow each
    Message 1 of 53 , Dec 2, 2003
      Johan,

      Your post is quite complex because you mention both, batch and
      continuous disitllation.

      With batch distillation, all the fractions will follow each other in
      time and they all, sooner or later appear at the top of the column
      and can be caught there.
      The temperature at the top of the column is the indicator of the
      fraction showing up at any time.
      These fractions become more distinct with a rising amount of stages.
      If the column is higher it's easier to make specific "cuts", so also
      of the unwanted fractions.

      Continuous distillation is another story, because all the fractions
      continuously appear at the same time and not "one after the other" as
      during batch distillation.

      Regards,
      Dirk



      --- In new_distillers@yahoogroups.com, "Johan" <mugg@h...> wrote:
      > Johan,
      >
      > Let's consider this still as a normal reflux still and a vapour
      > management arm is added on the other side.
      >
      > While the still is stabilizing and the heads are collected, we keep
      > the gate valve towards the distillate condensor well closed.
      >
      > Only after the heads are removed, this gate valve is opened and
      > basically untainted ethanol is collected.
      >
      > Yes, the heads can taint the reflux condensor, but they also taint
      > the scrubbers. I think that the most important issue is to consider
      > that a separate collection valve under the main (reflux) condensor
      can
      > remove the bulk of those heads and eventually later on, if one
      would
      > wish, ethanol and tails.
      >
      > Now, I haven't done this in practice, but I can easily imagine
      that,
      > doing so, will result in a less tainted product. Must be. The
      > distillate condensor is only used when desired. This can be be for
      > very clean alcohol, when one uses a high column or a high reflux
      rate.
      >
      > Of course, if the heads cannot not be bled off somewhere else, they
      > are bound to condense in the distillate condensor and taint it.
      >
      > Regards,
      > Dirk
      >
      > ___________________________
      > Or something like this (almost as you said but with packing also)
      > Column with packing, lm valve, 20 cm packing, lm valve, condenser
      >
      > Bleed of head at the top valve to begin with, then open bottom head,
      > this valve shouldn't be tainted by now, lets say we use reflux
      ratio 10
      > on that.
      > If there is any remaining head in the vapour from the boiler, about
      one
      > tenth of the amount will be removed through that valve, remaining
      will
      > go up through the remaining packing and condense at the top, this
      valve
      > can be set to bleed off head slowly (or be closed and opened once
      in a
      > while). Maybe make a head that have rather much hold up of liquid
      to act
      > like a buffer. The tainted alcohol will run back through the top 20
      cm
      > packing that can strip off head back to the top (some will come back
      > down to bottom valve but the amount is greatly reduced).
      >
      > I tested this with the continuous still and the quality is good. It
      > isn't completely free from head (it can't be as head is fed
      continually)
      > but there wasn't much present ( I used 30 cm of packing between the
      > valves).
      >
      > If distilled directly from mash in a batch still I can imagine that
      this
      > will improve quality. I don't know what it is that comes from mash
      but
      > personally I think it sprits becomes a little yeasty like in odour,
      even
      > if head is bleed off at the beginning. With a long column and a head
      > removal thing quality is good if the reflux ratio is high.
      >
      > But I'm going to test something better, a side stripper that removes
      > head continually (first a normal column and the alcohol from that
      is fed
      > to a second column at the middle of the height, head goes to top,
      > alcohol to bottom). First test was a failure because the stripper
      didn't
      > get enough heat. I'm going to test this soon though with a better
      heat
      > "stealer" as heat is taken from first column, just waiting for one
      > copper cup. Basically it's for continuous stills but I think it'll
      work
      > well enough even for batch if the boiler contains mash. With a
      little
      > luck it might be able to remove that yeasty smell directly at the
      first
      > run so quality is fine or at least be able to skip removal of head
      in
      > the second run since this is done by itself. If the stripper is good
      > enough, the bottom of the stripper should contain nothing but
      alcohol
      > and never get tainted.
      >
      > Johan
    • Mike Nixon
      Shane Kirkman wrote: Subject: Re: [new_distillers] Re: [Distillers] Vapor management versus reflux control So would a cup or 2 of boiling water tipped down the
      Message 53 of 53 , Dec 9, 2003
        Shane Kirkman wrote:
        Subject: Re: [new_distillers] Re: [Distillers] Vapor management versus
        reflux control

        So would a cup or 2 of boiling water tipped down the condenser tube after
        the heads are removed help remove the tainting?
        ===============
        Hi Shane,

        It might, although you usually need to give components a good scrubbing with
        detergent, or soak in some active cleanser, to really shift those
        contaminants.

        Frankly, I wouldn't worry about it. What we are talking about here is a
        tiny amount of additional purification which is probably only worth
        bothering about if you are after ultra pure ethanol for use with scents or
        essences. In that case it is then probably better to go the 'dedicated
        path' way and try to keep as much of the heads away from your main product
        collection path.

        Just shows how far we have all come on this list (which was supposed to be
        for newbies!) that we are now discussing removal of trace compounds! Just a
        couple of years ago it was "what the hell is distillation?" :-)

        Cheers!
        Mike N
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