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Re: Reflux Valve = Temperature Controller (?)

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  • peter_vcb
    hi Mike makes lots of sense, thanks. i did an excel file after i posted yesterday to see the variance in the ratio just like you mention. i got different
    Message 1 of 17 , Apr 1, 2003
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      hi Mike
      makes lots of sense, thanks. i did an excel file after i posted
      yesterday to see the variance in the ratio just like you mention. i
      got different ratios than you (i used mm) but same ratios between
      diameters (i.e. 1/2" was 4 times 2"). i tried putting them into Tonys
      calculators but gave up quickly! Johan initialy had an undeformed
      tube and still got high strength. i am planning on making one with
      several columns. i found out 1/2" 316 s/s tube is cheaper than copper
      for me so i will use that (just over 2euro per metre). i figure that
      i can add many columns and if they are tall enough and identical i
      should get an even output from each of them (and hence run at high
      power). i am thinking of columns 4 or 5 metres high without
      insulation for the top metre to cause some ambient reflux. i think if
      they are outdoors then the long fall of 4 metres on the output side
      may mean they need no cooling at all. i will make one and get it
      right before replicating the other columns.

      Peter

      --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
      > peter_vcb wrote:
      > Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?)
      >
      > MIKE N- could you please comment on Johans 1/2" copper tube still.
      > 95% from a 3% wash with no packing, what is going on there! all i
      can consider is that the tube is so narrow that the vapour is exposed
      to a large surface area just like packing.
      > =============================
      > Hi Peter,
      >
      > I'll give it a go, but first thanks to Johan for the pic. Helps a
      lot, so I've shoved it in here as well
      > Rodmac is right ... with those indentations it's reminiscent of a
      Vigreux condenser that has its internal surface area increased by
      lots of indentations.
      >
      > As I see it, the main feature of Johan's procedure is that it is
      deliberately kept very slow, so the vapor is moving up this column at
      a very low speed indeed. As in a lyne arm, vapor will condense on
      the walls and some of this liquid will be re-evaporated to give vapor
      with a higher concentration of volatiles. Stripped liquid will
      accumulate and trickle back down, and the richer vapor will condense
      a little further up to repeat the process. As the vapor speed is
      very low, we can think of the column in Tony's terms as having a very
      small HETP, so we can envisage this liquid/vapor interchange being
      repeated many, many times before the vapor reaches the top, resulting
      in good separation.
      >
      > The low speed of the vapor is one important factor. The other is
      the surface/volume ratio. Same reasoning that we use with
      packing ... the greater the surface area of the liquid in a given
      volume of vapor, then the more efficient the evaporation interchange
      will be. Now the ratio between the internal surface area of a tube
      and its volume (which will be the same thing as liquid surface
      area/vapor volume) is very simple: it's 4/D, where D is the
      diameter. Other things like length and Pi all cancel out. Johan is
      using 1/2" diameter tubing, so the ratio is 8. Compare this with,
      say, a 2" diameter tube where the ratio is just 2. He has also
      increased this ratio slightly by getting busy with his trusty Thor's
      Hammer, so the ratio could possibly be nearer 9 than 8. We can also
      see that if he had used 1/4" diameter tubing them the ratio would be
      up to 16.
      >
      > I reckon that it is this combination of slow vapor speed and fairly
      high surface/volume ratio that makes Johan's method work so well. I
      would also think that using several 1/4" diameter tubes would be even
      better ... the surface/volume ratio would remain the same of course
      (16), but the volume being processed would increase with every extra
      tube used. However, if anyone cares to see is this works, I wouldn't
      bother with the indentations. They are a good idea with 1/2" tubing,
      but the slight increase in surface area you would get with 1/4"
      diameter wouldn't be worth mangling a bunch of nice copper tubing
      that could be used for other purposes at another time.
      >
      > Make any sense?
      >
      > Mike N
    • Mike Nixon
      peter_vcb wrote: Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?) hi Mike makes lots of sense, thanks. i did an excel file after i posted
      Message 2 of 17 , Apr 1, 2003
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        peter_vcb wrote:
        Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?)

        hi Mike
        makes lots of sense, thanks. i did an excel file after i posted yesterday to see the variance in the ratio just like you mention. i
        got different ratios than you (i used mm)  .....
        ============================
        Hi Peter,
        The way I figured it, the circumference of a cylinder diameter D is (Pi)D, so the surface area is(Pi)DL
        The volume of that cylinder is (Pi)D2L/4
        so the ratio of surface area/volume came to 4(Pi)DL / (Pi)D2L  .... or 4/D
        Snag is, the dimensions of this are "per length" so yes, the number you get will indeed depend on what units you use, so it's better to get rid of that length by comparing different tubes to get a dimensionless number.
         
        So if we compare tube A with diameter Da with tube B with diameter Db we get TubeA/Tube B = Db/Da
        Suppose Tube A is 1/4 inches diameter and tube B is 2 inches diameter, we get Db/Da = 2*4 = 8
        In metric terms ... Tube A is 1/4 * 25.5 mm diameter and tube B is 2 * 25.4 mm diameter, and the ratio is again 8.
        In words, Tube A has 8 times as much surface area per volume than tube B
         
        Better?
        Mike N
      • homedistiller
        Hi all, I also follow, with interest, the pipe column experiments. On the next page, it says that a single, (insulated of course!) open tube column of 6 mm
        Message 3 of 17 , Apr 2, 2003
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          Hi all,
          I also follow, with interest, the "pipe column" experiments.
          On the next page, it says that a single, (insulated of course!) open
          tube column of 6 mm (.25 inch) has a plate height of 80 cm for a
          throughput of 10 ml/minute.

          http://ull.chemistry.uakron.edu/chemsep/slide.html$Chapter=/chemsep/
          distillation/&Last=34&Slide=31

          I was thinking of just stretching a thin polypropylene rope, copper
          electricity wire, stainless steel cable (2 or 3 mm diameter ?) inside
          this column.
          The slightest obstruction inside this pipe would instantly reduce the
          plate height and thus create many more stages for the same length of
          pipe. It would increase the contact surface, would reduce the
          downward velocity of the reflux and a rope or a cable can be easily
          removed for cleaning purposes.

          As Mike Nixon proposed already in an earlier post, similar of those
          "pipe columns" can be bundled in parallel.

          Dirk




          --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
          > peter_vcb wrote:
          > Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?)
          >
          > hi Mike
          > makes lots of sense, thanks. i did an excel file after i posted
          yesterday to see the variance in the ratio just like you mention. i
          > got different ratios than you (i used mm) .....
          > ============================
          > Hi Peter,
          > The way I figured it, the circumference of a cylinder diameter D is
          (Pi)D, so the surface area is(Pi)DL
          > The volume of that cylinder is (Pi)D2L/4
          > so the ratio of surface area/volume came to 4(Pi)DL / (Pi)D2L ....
          or 4/D
          > Snag is, the dimensions of this are "per length" so yes, the number
          you get will indeed depend on what units you use, so it's better to
          get rid of that length by comparing different tubes to get a
          dimensionless number.
          >
          > So if we compare tube A with diameter Da with tube B with diameter
          Db we get TubeA/Tube B = Db/Da
          > Suppose Tube A is 1/4 inches diameter and tube B is 2 inches
          diameter, we get Db/Da = 2*4 = 8
          > In metric terms ... Tube A is 1/4 * 25.5 mm diameter and tube B is
          2 * 25.4 mm diameter, and the ratio is again 8.
          > In words, Tube A has 8 times as much surface area per volume than
          tube B
          >
          > Better?
          > Mike N
        • peter_vcb
          Mike, yep i was working the same way using mm and using a standard length of 1m. so do you think Johans coiled copper tube idea would work as well or even
          Message 4 of 17 , Apr 2, 2003
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            Mike,
            yep i was working the same way using mm and using a standard length
            of 1m.
            so do you think Johans coiled copper tube idea would work as well or
            even better? if coiled the cooled vapour will flow down the tube
            whereas if it is vertical it may fall straight down and the tube may
            experience less wetting of the available surface. conversely it will
            only flow on the lower section of the tube so vertical may be better.
            if a coiled one would work it would easier to use indoors you could
            have 10metres coiled to a low height. it could coil up fully
            insulated and coil back down over itself with a fan blowing on it. i
            still have this idea of a nice efficient radiator in my room pumping
            out booze all day and keeping me warm :-)

            if it scaled up perfectly (i know it wont) a 2" column would need to
            be 6m high to work the same as the 1/2" 1.5m column. the cross
            section area of a 2" column is 16 times that of a 1/2" column. so to
            run at the same power i would need 16 columns at 1.5m which is 24m of
            1/2" tube (56euro to me) compared to 6m of 2" tube (105euro). so has
            anybody heard of a very high column run with no scrubbers? cheaper
            than copper of s/s would be scaffolding poles. you could get 6m very
            cheap and redistill the output to leave the nasties behind.

            Peter


            --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
            > peter_vcb wrote:
            > Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?)
            >
            > hi Mike
            > makes lots of sense, thanks. i did an excel file after i posted
            yesterday to see the variance in the ratio just like you mention. i
            > got different ratios than you (i used mm) .....
            > ============================
            > Hi Peter,
            > The way I figured it, the circumference of a cylinder diameter D is
            (Pi)D, so the surface area is(Pi)DL
            > The volume of that cylinder is (Pi)D2L/4
            > so the ratio of surface area/volume came to 4(Pi)DL / (Pi)D2L ....
            or 4/D
            > Snag is, the dimensions of this are "per length" so yes, the number
            you get will indeed depend on what units you use, so it's better to
            get rid of that length by comparing different tubes to get a
            dimensionless number.
            >
            > So if we compare tube A with diameter Da with tube B with diameter
            Db we get TubeA/Tube B = Db/Da
            > Suppose Tube A is 1/4 inches diameter and tube B is 2 inches
            diameter, we get Db/Da = 2*4 = 8
            > In metric terms ... Tube A is 1/4 * 25.5 mm diameter and tube B is
            2 * 25.4 mm diameter, and the ratio is again 8.
            > In words, Tube A has 8 times as much surface area per volume than
            tube B
            >
            > Better?
            > Mike N
          • Aaron Pelly
            Did you never get your low power input-air cooled-heater-still to work? I had forgotten about it actually. What progress _did_ you make? ... ...
            Message 5 of 17 , Apr 2, 2003
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              Did you never get your low power input-air cooled-heater-still to work?

              I had forgotten about it actually.

              What progress _did_ you make?

              > -----Original Message-----
              > From: peter_vcb [mailto:viciousblackout@...]
              > Sent: Wednesday, 2 April 2003 21:55
              > To: Distillers@yahoogroups.com
              > Subject: [Distillers] Re: Reflux Valve = Temperature Controller (?)

              <snip>
              > i
              > still have this idea of a nice efficient radiator in my room pumping
              > out booze all day and keeping me warm :-)
              <snip>
            • peter_vcb
              Hi Aaron i never actually tried it (it is made though). i made the air stripping still instead but it stank my room out and that was at 60C. my fan didnt have
              Message 6 of 17 , Apr 2, 2003
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                Hi Aaron
                i never actually tried it (it is made though). i made the air
                stripping still instead but it stank my room out and that was at 60C.
                my fan didnt have much of a cooling effect on that so i presumed it
                would have had very little effect if it was actually boiling.

                for those who missed it my plan was to have my own reflux still run
                at such low power that it would only need air cooling and i could
                leave it on all day long. i ran my reflux still it at about 600W and
                got about 600ml per hour. if i made an "air liebeg" it may work. a
                large diameter pvc tube with the copper outlet tube in it and a fan
                blowing up it. Johans 1.5m 1/2" copper tube is a better and cheaper
                bet, very easy to make and gives the same output. if the copper
                outlet (or downturn on Johans) is long enough then it will cool by
                ambient air if the power is low enough. otherwise i would have the
                tube going into a worm in a bucket of water which would be changed
                daily. my other idea is an outdoor still like Johans 1/2" tube but
                have it about 5m high so it will be completely cool by the time it
                travels downturned 5m of tube. the downturn tube could also be filled
                with carbon to slow the distillate down to allow more cooling.

                Peter


                --- In Distillers@yahoogroups.com, "Aaron Pelly" <apelly@m...> wrote:
                > Did you never get your low power input-air cooled-heater-still to
                work?
                >
                > I had forgotten about it actually.
                >
                > What progress _did_ you make?
                >
                > > -----Original Message-----
                > > From: peter_vcb [mailto:viciousblackout@y...]
                > > Sent: Wednesday, 2 April 2003 21:55
                > > To: Distillers@yahoogroups.com
                > > Subject: [Distillers] Re: Reflux Valve = Temperature Controller
                (?)
                >
                > <snip>
                > > i
                > > still have this idea of a nice efficient radiator in my room
                pumping
                > > out booze all day and keeping me warm :-)
                > <snip>
              • mwmccaw
                Peter, what you are describing begins to sound a lot like a gas chromatography column, which is often a very long coil of very fine tubing. The key problem I
                Message 7 of 17 , Apr 2, 2003
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                  Peter, what you are describing begins to sound a lot like a gas
                  chromatography column, which is often a very long coil of very fine
                  tubing.
                  The key problem I see with what you describe will be heat loss - the
                  smaller the column diameter, the faster the heat loss per unit
                  length, so there will be a maximum length you can run - as soon as
                  the column temperature falls below 78 deg C, you're hosed....
                  You're right that you would have more potential area for reflux, and
                  that it should proceed downward more slowly, but it will also only
                  coat a fraction of the tube diameter.
                  In short, worthy of an experiment!
                  Mike McCaw



                  --- In Distillers@yahoogroups.com, "peter_vcb"
                  <viciousblackout@y...> wrote:
                  > Mike,
                  > yep i was working the same way using mm and using a standard
                  length
                  > of 1m.
                  > so do you think Johans coiled copper tube idea would work as well
                  or
                  > even better? if coiled the cooled vapour will flow down the tube
                  > whereas if it is vertical it may fall straight down and the tube
                  may
                  > experience less wetting of the available surface. conversely it
                  will
                  > only flow on the lower section of the tube so vertical may be
                  better.
                  > if a coiled one would work it would easier to use indoors you
                  could
                  > have 10metres coiled to a low height. it could coil up fully
                  > insulated and coil back down over itself with a fan blowing on it.
                  i
                  > still have this idea of a nice efficient radiator in my room
                  pumping
                  > out booze all day and keeping me warm :-)
                  >
                  > if it scaled up perfectly (i know it wont) a 2" column would need
                  to
                  > be 6m high to work the same as the 1/2" 1.5m column. the cross
                  > section area of a 2" column is 16 times that of a 1/2" column. so
                  to
                  > run at the same power i would need 16 columns at 1.5m which is 24m
                  of
                  > 1/2" tube (56euro to me) compared to 6m of 2" tube (105euro). so
                  has
                  > anybody heard of a very high column run with no scrubbers? cheaper
                  > than copper of s/s would be scaffolding poles. you could get 6m
                  very
                  > cheap and redistill the output to leave the nasties behind.
                  >
                  > Peter
                  >
                  >
                  > --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
                  > > peter_vcb wrote:
                  > > Subject: [Distillers] Re: Reflux Valve = Temperature Controller
                  (?)
                  > >
                  > > hi Mike
                  > > makes lots of sense, thanks. i did an excel file after i posted
                  > yesterday to see the variance in the ratio just like you mention.
                  i
                  > > got different ratios than you (i used mm) .....
                  > > ============================
                  > > Hi Peter,
                  > > The way I figured it, the circumference of a cylinder diameter D
                  is
                  > (Pi)D, so the surface area is(Pi)DL
                  > > The volume of that cylinder is (Pi)D2L/4
                  > > so the ratio of surface area/volume came to 4(Pi)DL / (Pi)
                  D2L ....
                  > or 4/D
                  > > Snag is, the dimensions of this are "per length" so yes, the
                  number
                  > you get will indeed depend on what units you use, so it's better
                  to
                  > get rid of that length by comparing different tubes to get a
                  > dimensionless number.
                  > >
                  > > So if we compare tube A with diameter Da with tube B with
                  diameter
                  > Db we get TubeA/Tube B = Db/Da
                  > > Suppose Tube A is 1/4 inches diameter and tube B is 2 inches
                  > diameter, we get Db/Da = 2*4 = 8
                  > > In metric terms ... Tube A is 1/4 * 25.5 mm diameter and tube B
                  is
                  > 2 * 25.4 mm diameter, and the ratio is again 8.
                  > > In words, Tube A has 8 times as much surface area per volume
                  than
                  > tube B
                  > >
                  > > Better?
                  > > Mike N
                • Johan
                  I agree that heatloss probably is a problem, but insulate it may not be so hard since it is a coil. Johan Peter, what you are describing begins to sound a lot
                  Message 8 of 17 , Apr 2, 2003
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                    I agree that heatloss probably is a problem, but insulate it may not be so
                    hard since it is a coil.

                    Johan

                    Peter, what you are describing begins to sound a lot like a gas
                    chromatography column, which is often a very long coil of very fine
                    tubing.
                    The key problem I see with what you describe will be heat loss - the
                    smaller the column diameter, the faster the heat loss per unit
                    length, so there will be a maximum length you can run - as soon as
                    the column temperature falls below 78 deg C, you're hosed....
                    You're right that you would have more potential area for reflux, and
                    that it should proceed downward more slowly, but it will also only
                    coat a fraction of the tube diameter.
                    In short, worthy of an experiment!
                    Mike McCaw



                    --- In Distillers@yahoogroups.com, "peter_vcb"
                    <viciousblackout@y...> wrote:
                    > Mike,
                    > yep i was working the same way using mm and using a standard
                    length
                    > of 1m.
                    > so do you think Johans coiled copper tube idea would work as well
                    or
                    > even better? if coiled the cooled vapour will flow down the tube
                    > whereas if it is vertical it may fall straight down and the tube
                    may
                    > experience less wetting of the available surface. conversely it
                    will
                    > only flow on the lower section of the tube so vertical may be
                    better.
                    > if a coiled one would work it would easier to use indoors you
                    could
                    > have 10metres coiled to a low height. it could coil up fully
                    > insulated and coil back down over itself with a fan blowing on it.
                    i
                    > still have this idea of a nice efficient radiator in my room
                    pumping
                    > out booze all day and keeping me warm :-)
                    >
                    > if it scaled up perfectly (i know it wont) a 2" column would need
                    to
                    > be 6m high to work the same as the 1/2" 1.5m column. the cross
                    > section area of a 2" column is 16 times that of a 1/2" column. so
                    to
                    > run at the same power i would need 16 columns at 1.5m which is 24m
                    of
                    > 1/2" tube (56euro to me) compared to 6m of 2" tube (105euro). so
                    has
                    > anybody heard of a very high column run with no scrubbers? cheaper
                    > than copper of s/s would be scaffolding poles. you could get 6m
                    very
                    > cheap and redistill the output to leave the nasties behind.
                    >
                    > Peter
                    >
                    >
                    > --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
                    > > peter_vcb wrote:
                    > > Subject: [Distillers] Re: Reflux Valve = Temperature Controller
                    (?)
                    > >
                    > > hi Mike
                    > > makes lots of sense, thanks. i did an excel file after i posted
                    > yesterday to see the variance in the ratio just like you mention.
                    i
                    > > got different ratios than you (i used mm) .....
                    > > ============================
                    > > Hi Peter,
                    > > The way I figured it, the circumference of a cylinder diameter D
                    is
                    > (Pi)D, so the surface area is(Pi)DL
                    > > The volume of that cylinder is (Pi)D2L/4
                    > > so the ratio of surface area/volume came to 4(Pi)DL / (Pi)
                    D2L ....
                    > or 4/D
                    > > Snag is, the dimensions of this are "per length" so yes, the
                    number
                    > you get will indeed depend on what units you use, so it's better
                    to
                    > get rid of that length by comparing different tubes to get a
                    > dimensionless number.
                    > >
                    > > So if we compare tube A with diameter Da with tube B with
                    diameter
                    > Db we get TubeA/Tube B = Db/Da
                    > > Suppose Tube A is 1/4 inches diameter and tube B is 2 inches
                    > diameter, we get Db/Da = 2*4 = 8
                    > > In metric terms ... Tube A is 1/4 * 25.5 mm diameter and tube B
                    is
                    > 2 * 25.4 mm diameter, and the ratio is again 8.
                    > > In words, Tube A has 8 times as much surface area per volume
                    than
                    > tube B
                    > >
                    > > Better?
                    > > Mike N



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