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RE: [biofuel] RE: [Distillers] Collecting impurities

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  • Robert Warren
    ... From: Tony & Elle Ackland To: Distillers , Biofuel Sent: June
    Message 1 of 2 , Jun 3, 2000
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      ------Original Message------
      From: Tony & Elle Ackland
      <Tony.Ackland@...>
      To: "'Distillers'" <Distillers@egroups.com>,
      "'Biofuel'" <biofuel@egroups.com>
      Sent: June 4, 2000 12:20:21 AM GMT
      Subject: RE: [biofuel] RE: [Distillers] Collecting
      impurities

      Robert,
      Thanks for the reply. I have a couple of
      questions/myths that you might help me with...

      >However, the doubler (or thumper, as
      >some people call it) did most of the work of
      >removing the methanol as it was easily flash
      >cooled by the water in the doubler. Perhaps even
      >more important is the fact that the methanol is
      >easily soluble in the water, and that it is the
      >fact that methanol is a more aggressive solvent
      >(in other words, faster to react with other
      >elements) which makes it react quickly with the
      >water and therefore enter into a chemical mixture
      >or compound.

      How is it that the methanol forms a more positive
      bond with the water in the doubler, compared to
      the water in the original wash? I can understand
      it initially being collected in there when the
      doubler is cold, but doesn't this heat up after a
      while (because of the hot vapours passing through
      it), and then the methanol will start to come out
      of solution as easily as it
      did off the inital wash ? I haven't seen a
      doubler in action, but I'd figure that it would be
      operating at around 82-85C after a while - warm
      enough to vaporise a fair bit of its methanol.

      What sort of reaction is taking place - what are
      the compounds it forms ? I had presumed that it
      would be fairly inert toward water. Why wouldn't
      these form (& stay) in the inital wash too ?

      Dear Tony,
      It has to do with the fact that you have a flame
      or an electric heating element under your cooking
      pot. The point of contact with the heat source may
      be well over 120 C or more, depending on what you
      are using for fuel and how closely it is
      controlled. The beer or wash solution is where
      you are applying an excess of heat, really, to
      boil the water which means you need to apply over
      100 C heat, and both the ethanol and methanol are
      boiling long before the water is. Actually, as you
      know from your graphs that you put up on your web
      site, the whole mix is boiling at a lower
      temperature according to the alcohol concentration
      you have. The water in the doubler does indeed
      heat up during the process, but the methanol as a
      vapor is having to pass through a liquid barrier
      (same as the ethanol does) but having more free
      electron holes for the hydrogen atoms of the water
      molecules to adhere to, this happens very quickly.
      If your thumper or doubler is at the bottom of the
      reflux column (rather than isolated as a separate,
      non-attached device like I have seen on some older
      style stills, then in addition to the heat coming
      in from the bottom of the doubler, you also have
      cooling water coming down from above in the relux
      column. This is why your doubler water stays
      liquid: it is getting cooled by water dripping
      from above. Also, this water adds up and has to
      drain out the bubbler overflow drain, because you
      don't want this level to get too high or it will
      begin to trap ethanol, as well.
      This higher the surface area of your packing
      materials inside the reflux column, the better
      this works, as you also have a constant heating
      effect going up and a cooling effect of water
      trickling down. Perhaps only half of the ethanol
      vapors make it up to the top the first time
      through, more likely it is getting condenced
      somewhere midway up the reflux column and falling
      down only to get caught by surface tension on the
      packing material and then re-heated by steam
      rising from below. So there is a surface tension
      phenomon going on withthe packing materials, as
      well.
      If you look at the dynamics of a large commercial
      still, you will find that rather than random
      packing, they have actual flat plates with holes
      in them so there is quite a baffling effect and
      lots of surface area for the up and down reflux
      action to take place. They have calibrated ahead
      of time the exact surce area of all this packing,
      and then know the flow rates ahead of time, as it
      is a standard thermodynamic heat exchanger
      calculation. (I can no longer do the math, but I
      have seen how it is calculated).
      These commercial stills are usually about 10
      meters tall, and they run continuously, instead of
      doing separate batches. The way it works is the
      beer is fed as a liquid by a pump into a port near
      the top of the reflux column, and live steam is
      introducted at the bottom. The steam will also
      have an alcohol content, but you have quite a
      series of waterfalls inside the 25 cm or larger
      column which is the reflux tower. Temperatures
      and flow rates are qute closely controlled, and
      the column is usually insultated so as to
      eliminated any lack of control due to outside
      temperature conditions. So in a large
      commercial still, you have the same process, only
      on a larger scale, and there is very little chance
      that any methanol will get through as it bonds so
      easily to the bottoms water. The other thing to
      remember is the amount o fmethanol is a very small
      percentage, overall compared to your ethanol
      content. Usually in a 5 % beer you will only have
      maybe .1 %, or problaby even lower than that. I
      don't have any of my refernce books on alcohol
      anymore, I sent them all to Keith for use by the
      Biofuel's group, so my figures could be off due to
      the fact that I am just trying to recall stuff I
      read about 25 yrs ago when I was getting started
      in all this.

      >Now, the fusil oils get trapped for a
      >different reason. They are also easily removed by
      >the water which is cooling the vapors, but then
      it
      >gets trapped by the surface tension of the water.
      >It floats to the top, and gets poured off with
      the
      >bottoms water.

      I wonder if anyone has tried using surface tension
      modifiers to get this happening a little better,
      non-ionic surfactants and the like ? There must be
      a suitable one out there which would enhance this
      feature.

      Now, here you are talking about something which is
      going to introduce another chemical or possibly a
      bad taste to the mix.
      Leave well enough alone, and if you do have any
      methanol, it will certainly come out in the
      charcoal filtering and aging processes.
      The charcoal will remove complex organic
      pollutants which you didn't even know you had. The
      limitations of carbon filters is that they con't
      remove non-organic pollutants like lead, mercury,
      cadmium, and other such metalic pollutants.
      However, carbon filters fo a fairly nice job of
      removing chlorine and chlorine compunds, and that
      is great, as some of the chlorine compounds can be
      fairly nasty in small doses.
      This is a separate issue completely, but if you
      ever travel in Mexico or China, it is never safe
      to drink the water, but pretty much always safe to
      drink the beer. The beer factories usually have
      pretty good water filtration, then the alcohol
      kills off the microbes. When I was living in China
      last year, they had one kind of beer that had a
      big ass ugly beetle inside the bottle. A friend
      from the US came to visit me, and when we were in
      the Chinese market, he bought a couple bottles of
      wine to take home (just for display, he didn't
      want to drink it) called "Three snakes wine".
      There were three poisonous snakes curled up inside
      just one wine bottle. Now, I know they put the
      worm in the Tequila bottle in Mexico, but perhaps
      those of you who are looking for an exotic flavor
      ought to consider adding other live critteres to
      your high proof if you are adventurous enough to
      go off exploring new taste terriories.


      I had presumed that they were retained here (more
      than in the wash) because
      of the doublers lower temperature than the wash
      (eg 90-96C), and hence lower volitility.

      Yes, that is also true. It is both the lower temp
      and the reacting with water.
      cheers,
      Robert

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      robertwarren@...

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