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Advantage of tall column

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  • tyler_97355
    What would be the advantage of having a 10 foot column over a 5 foot column? Would i be able to put more power through it? Would it just sepperate better? Are
    Message 1 of 13 , Oct 30, 2006
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      What would be the advantage of having a 10 foot column over a 5 foot
      column? Would i be able to put more power through it? Would it just
      sepperate better? Are there any disadvantages?

      -Tyler
    • Harry
      ... If you double the available volume to fill per timeslice, then you can double the power input (approx). Disadvantages are: More expense in materials;
      Message 2 of 13 , Oct 31, 2006
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        --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
        wrote:
        >
        > What would be the advantage of having a 10 foot column over a 5 foot
        > column? Would i be able to put more power through it? Would it just
        > sepperate better? Are there any disadvantages?
        >
        > -Tyler
        >



        If you double the available volume to fill per timeslice, then you can
        double the power input (approx). Disadvantages are: More expense in
        materials; more insulation is necessary.

        The usual method of designing a column is first to decide what amount
        of product per hour you want to produce. Then design a column, HETP
        and power input that will achieve that rate and purity; then design a
        condenser that will accomodate that power input for total reflux,
        because it's necessary to perform total reflux for a certain amount of
        time before taking product.


        Slainte!
        regards Harry
      • fit_dude42
        Maybe i misunderstood some of the info when i was building my still but please correct me if i m wrong. The height of the column combined with the type of
        Message 3 of 13 , Oct 31, 2006
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          Maybe i misunderstood some of the info when i was building my still
          but please correct me if i'm wrong.

          The height of the column combined with the type of packing
          controlled the purity %age of the product, as you get a higher HETP
          from a taller column and greater height of packing.

          The column diameter was the primary limitation on vapour flow so a
          smaller diameter column would not flow as much vapour as a larger
          diameter column, and vapour flow was controlled by how much power
          was being used in the boiler i.e. how much vapour it could produce.

          Have i got this wrong, or just misunderstood the principles involved?

          Karl.

          Cheers m'dears.



          --- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
          wrote:
          >
          > --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@>
          > wrote:
          > >
          > > What would be the advantage of having a 10 foot column over a 5
          foot
          > > column? Would i be able to put more power through it? Would it
          just
          > > sepperate better? Are there any disadvantages?
          > >
          > > -Tyler
          > >
          >
          >
          >
          > If you double the available volume to fill per timeslice, then you
          can
          > double the power input (approx). Disadvantages are: More expense
          in
          > materials; more insulation is necessary.
          >
          > The usual method of designing a column is first to decide what
          amount
          > of product per hour you want to produce. Then design a column,
          HETP
          > and power input that will achieve that rate and purity; then
          design a
          > condenser that will accomodate that power input for total reflux,
          > because it's necessary to perform total reflux for a certain
          amount of
          > time before taking product.
          >
          >
          > Slainte!
          > regards Harry
          >
        • Harry
          ... still ... HETP ... ...................Same power input, taller column = same HETP, more plates. More power input, taller column = expanded HETP (each plate
          Message 4 of 13 , Oct 31, 2006
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            --- In new_distillers@yahoogroups.com, "fit_dude42" <fit_dude42@...>
            wrote:
            >
            > Maybe i misunderstood some of the info when i was building my
            still
            > but please correct me if i'm wrong.
            >
            > The height of the column combined with the type of packing
            > controlled the purity %age of the product, as you get a higher
            HETP
            > from a taller column and greater height of packing.




            ...................Same power input, taller column = same HETP, more
            plates.
            More power input, taller column = expanded HETP (each plate is
            taller/deeper), less plates for given height.



            >
            > The column diameter was the primary limitation on vapour flow so a
            > smaller diameter column would not flow as much vapour as a larger
            > diameter column,



            ...........Ever seen the steam fly out of a pressure cooker when you
            remove the wobbler valve? That's a very small aperture it's coming
            from (think small diam column), and it doesn't bother the steam
            volume at all. But it DOES have a marked bearing on the SPEED
            upwards of said steam.


            and vapour flow was controlled by how much power
            > was being used in the boiler i.e. how much vapour it could produce.



            ........Vapour VOLUME CREATED is governed by power input. The flow
            of the vapour only changes speed-wise, not volume-wise. See above.



            >
            > Have i got this wrong, or just misunderstood the principles
            involved?
            >
            > Karl.
            >
            > Cheers m'dears.



            Slainte!
            regards Harry
          • fit_dude42
            I stand corrected. I knew what i was trying to say just didn t get the terms right. The HETP will of course be the same it will just mean you have more
            Message 5 of 13 , Oct 31, 2006
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              I stand corrected. I knew what i was trying to say just didn't get
              the terms right. The HETP will of course be the same it will just
              mean you have more effective plates, which i believe would alter the
              %age?

              What i meant to say was that i had thought that the wider the column
              the more it can cope with without blowing the whole lot out the top
              due to the vapour rising under the higher power of the boiler?

              Does that make more correct sense?

              I built my still along the Bokakob 'mini-still' design but with a
              wider and taller column, using the very useful calculators on the
              home page, but hadn't quite worked out why it did what it did.

              Many thanks,

              Karl.


              --- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
              wrote:
              >
              > --- In new_distillers@yahoogroups.com, "fit_dude42" <fit_dude42@>
              > wrote:
              > >
              > > Maybe i misunderstood some of the info when i was building my
              > still
              > > but please correct me if i'm wrong.
              > >
              > > The height of the column combined with the type of packing
              > > controlled the purity %age of the product, as you get a higher
              > HETP
              > > from a taller column and greater height of packing.
              >
              >
              >
              >
              > ...................Same power input, taller column = same HETP,
              more
              > plates.
              > More power input, taller column = expanded HETP (each plate is
              > taller/deeper), less plates for given height.
              >
              >
              >
              > >
              > > The column diameter was the primary limitation on vapour flow so
              a
              > > smaller diameter column would not flow as much vapour as a
              larger
              > > diameter column,
              >
              >
              >
              > ...........Ever seen the steam fly out of a pressure cooker when
              you
              > remove the wobbler valve? That's a very small aperture it's
              coming
              > from (think small diam column), and it doesn't bother the steam
              > volume at all. But it DOES have a marked bearing on the SPEED
              > upwards of said steam.
              >
              >
              > and vapour flow was controlled by how much power
              > > was being used in the boiler i.e. how much vapour it could
              produce.
              >
              >
              >
              > ........Vapour VOLUME CREATED is governed by power input. The
              flow
              > of the vapour only changes speed-wise, not volume-wise. See above.
              >
              >
              >
              > >
              > > Have i got this wrong, or just misunderstood the principles
              > involved?
              > >
              > > Karl.
              > >
              > > Cheers m'dears.
              >
              >
              >
              > Slainte!
              > regards Harry
              >
            • abbababbaccc
              This is true up to a point of column flooding. However, the biggest advantage to tall columns as I see it is that you can run numerically lower reflux ratio to
              Message 6 of 13 , Oct 31, 2006
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                This is true up to a point of column flooding. However, the biggest
                advantage to tall columns as I see it is that you can run numerically
                lower reflux ratio to get similar results as with shorter columns.
                This in turn translates to a faster distillation.

                Cheers, Riku

                --- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...> wrote:

                >
                >
                > If you double the available volume to fill per timeslice, then you can
                > double the power input (approx). Disadvantages are: More expense in
                > materials; more insulation is necessary.
                >
                > The usual method of designing a column is first to decide what amount
                > of product per hour you want to produce. Then design a column, HETP
                > and power input that will achieve that rate and purity; then design a
                > condenser that will accomodate that power input for total reflux,
                > because it's necessary to perform total reflux for a certain amount of
                > time before taking product.
                >
                >
                > Slainte!
                > regards Harry
                >
              • Harry
                ... And this is because taller columns have more theoretical plates (obviously). Thus there are more distillations/separations as the vapour traverses the
                Message 7 of 13 , Oct 31, 2006
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                  --- In new_distillers@yahoogroups.com, "abbababbaccc"
                  <abbababbaccc@...> wrote:
                  >
                  > the biggest
                  > advantage to tall columns as I see it is that you can run numerically
                  > lower reflux ratio to get similar results as with shorter columns.
                  > This in turn translates to a faster distillation.


                  And this is because taller columns have more theoretical plates
                  (obviously). Thus there are more distillations/separations as the
                  vapour traverses the column length. So when you finally start
                  returning reflux, that returned mixture is far more concentrated in
                  ethanol than would be available in a shorter column. Therefore you
                  can afford to lower the ratio.

                  In theory, a column of sufficient length should require no reflux at
                  all, as the product arriving at the top would already be azeotrope.
                  However in practice, some reflux is desirable to provide the initial
                  downward-flowing liquid to initiate the separation/reboiling process.
                  Multiple-distillation fractionating columns (our 'reflux' type
                  stills), are a two-way action.


                  Slainte!
                  regards Harry
                • tyler_97355
                  Ow, my head is starting to hurt. Too much technical talk. lol. So if i have a 10 foot column of 2 copper pipe, i should be able to use more ower input, right?
                  Message 8 of 13 , Oct 31, 2006
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                    Ow, my head is starting to hurt. Too much technical talk. lol.

                    So if i have a 10 foot column of 2" copper pipe, i should be able to
                    use more ower input, right? Would i possibly be able to go up to
                    5.5kw like the PDA-2? I am assuming that if i raise the power input,
                    then i would not be able to reduce the reflux ratio. I am a little
                    confused by your reference to HETP and "plates". I thought it was the
                    same thing? I under stand that the more power, the more spead out the
                    plates are, therfore, you are limited by the hight of the column as
                    to how many plates you can have depending on you input power.

                    -Tyler



                    --- In new_distillers@yahoogroups.com, "Harry" <gnikomson2000@...>
                    wrote:
                    >
                    > --- In new_distillers@yahoogroups.com, "abbababbaccc"
                    > <abbababbaccc@> wrote:
                    > >
                    > > the biggest
                    > > advantage to tall columns as I see it is that you can run
                    numerically
                    > > lower reflux ratio to get similar results as with shorter columns.
                    > > This in turn translates to a faster distillation.
                    >
                    >
                    > And this is because taller columns have more theoretical plates
                    > (obviously). Thus there are more distillations/separations as the
                    > vapour traverses the column length. So when you finally start
                    > returning reflux, that returned mixture is far more concentrated in
                    > ethanol than would be available in a shorter column. Therefore you
                    > can afford to lower the ratio.
                    >
                    > In theory, a column of sufficient length should require no reflux
                    at
                    > all, as the product arriving at the top would already be
                    azeotrope.
                    > However in practice, some reflux is desirable to provide the
                    initial
                    > downward-flowing liquid to initiate the separation/reboiling
                    process.
                    > Multiple-distillation fractionating columns (our 'reflux' type
                    > stills), are a two-way action.
                    >
                    >
                    > Slainte!
                    > regards Harry
                    >
                  • abbababbaccc
                    A mesh/scrubber packed 2 column will flood at somewhere inbetween 2- 3kW. However, with 10 foot column you should be able to run at ~2kW and get more than
                    Message 9 of 13 , Oct 31, 2006
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                      A mesh/scrubber packed 2" column will flood at somewhere inbetween 2-
                      3kW. However, with 10 foot column you should be able to run at ~2kW
                      and get more than twice the output you'd get with 1 meter column
                      running at 1kW. In practise you should be able to run 2:1 or even
                      lower RR at the beginning instead of 5:1 or so that's typical. The
                      HETP is Height Equivalent To Plate. HETP is a function of packing
                      efficiency, vaporspeed and reflux ratio. And no, I don't have a
                      formula for that.

                      Cheers, Riku

                      --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
                      wrote:
                      >
                      > Ow, my head is starting to hurt. Too much technical talk. lol.
                      >
                      > So if i have a 10 foot column of 2" copper pipe, i should be able
                      to
                      > use more ower input, right? Would i possibly be able to go up to
                      > 5.5kw like the PDA-2? I am assuming that if i raise the power
                      input,
                      > then i would not be able to reduce the reflux ratio. I am a little
                      > confused by your reference to HETP and "plates". I thought it was
                      the
                      > same thing? I under stand that the more power, the more spead out
                      the
                      > plates are, therfore, you are limited by the hight of the column as
                      > to how many plates you can have depending on you input power.
                      >
                      > -Tyler
                      >
                      >
                      >
                    • abbababbaccc
                      A mesh/scrubber packed 2 column will flood at somewhere inbetween 2- 3kW. However, with 10 foot column you should be able to run at ~2kW and get more than
                      Message 10 of 13 , Oct 31, 2006
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                        A mesh/scrubber packed 2" column will flood at somewhere inbetween 2-
                        3kW. However, with 10 foot column you should be able to run at ~2kW
                        and get more than twice the output you'd get with 1 meter column
                        running at 1kW. In practise you should be able to run 2:1 or even
                        lower RR at the beginning instead of 5:1 or so that's typical. The
                        HETP is Height Equivalent To Plate. HETP is a function of packing
                        efficiency, vaporspeed and reflux ratio. And no, I don't have a
                        formula for that.

                        Cheers, Riku

                        --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
                        wrote:
                        >
                        > Ow, my head is starting to hurt. Too much technical talk. lol.
                        >
                        > So if i have a 10 foot column of 2" copper pipe, i should be able
                        to
                        > use more ower input, right? Would i possibly be able to go up to
                        > 5.5kw like the PDA-2? I am assuming that if i raise the power
                        input,
                        > then i would not be able to reduce the reflux ratio. I am a little
                        > confused by your reference to HETP and "plates". I thought it was
                        the
                        > same thing? I under stand that the more power, the more spead out
                        the
                        > plates are, therfore, you are limited by the hight of the column as
                        > to how many plates you can have depending on you input power.
                        >
                        > -Tyler
                        >
                        >
                        >
                      • tyler_97355
                        ok, so a 2 column flooding around 3kw is like my 1/2 liebig choking at 1.5kw when i tried to us it as a verticle reflux condenser, right? Too much liquid
                        Message 11 of 13 , Oct 31, 2006
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                          ok, so a 2" column "flooding" around 3kw is like my 1/2"
                          liebig "choking" at 1.5kw when i tried to us it as a verticle reflux
                          condenser, right? Too much liquid being condensed and staying in the
                          packing, which would impeed the vapor flow, and preasurize the still,
                          if i understand correctly. Which brings up another question. If your
                          info is correct, that a 2" column will flood if given a heat input
                          over 2-3kw, why is it that the PDA-2 will handle a max power input of
                          5.5kw? If i remember correctly, it is constucted with 2" pipe.

                          Once again, to make sure that i get the entirely clear definition of
                          HETP, the HETP is the height of packing that it takes to equal one
                          theoretical plate for the given tamperature, for that type of
                          packing? So, lets say, if the HETP for my still and its packing was 8
                          inches for each plate, if i increased my heat input, it might require
                          12 inches for each plate. I know that the measurements are not
                          correct, i am just wondering if i have the general idea down.

                          I do wonder, how does one aquire this knowledge? Does it take years
                          of engineering school, or is it just a matter of knowing the right
                          equations? I'm sorry if i am really slow with catching on to some of
                          the theory here, but thats why i'm in the "new distillers" forum, and
                          i really appreciate all of your help. Someday, i want you all to be
                          able to look back at me and say, "my god, what have we done!"

                          -Tyler
                        • Harry
                          ... reflux ... the ... still, ... your ... of ... ...........It s not 2 pipe. I can t remember which it is, either it s 3 or 4 , but definitely not 2 . ...
                          Message 12 of 13 , Nov 1, 2006
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                            --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...>
                            wrote:
                            >
                            > ok, so a 2" column "flooding" around 3kw is like my 1/2"
                            > liebig "choking" at 1.5kw when i tried to us it as a verticle
                            reflux
                            > condenser, right? Too much liquid being condensed and staying in
                            the
                            > packing, which would impeed the vapor flow, and preasurize the
                            still,
                            > if i understand correctly. Which brings up another question. If
                            your
                            > info is correct, that a 2" column will flood if given a heat input
                            > over 2-3kw, why is it that the PDA-2 will handle a max power input
                            of
                            > 5.5kw? If i remember correctly, it is constucted with 2" pipe.





                            ...........It's not 2" pipe. I can't remember which it is, either
                            it's 3" or 4", but definitely not 2".



                            >
                            > Once again, to make sure that i get the entirely clear definition
                            of
                            > HETP, the HETP is the height of packing that it takes to equal one
                            > theoretical plate for the given tamperature, for that type of
                            > packing?




                            .............AND that particular heat input.


                            So, lets say, if the HETP for my still and its packing was 8
                            > inches for each plate, if i increased my heat input, it might
                            require
                            > 12 inches for each plate.


                            .......Yes.


                            I know that the measurements are not
                            > correct, i am just wondering if i have the general idea down.


                            ..Yes.



                            >
                            > I do wonder, how does one aquire this knowledge? Does it take
                            years
                            > of engineering school,





                            ......The discipline is known as "Chemical Engineering" ChE for
                            short.


                            or is it just a matter of knowing the right
                            > equations?



                            ........ You can be 'self-taught' if you have a capacity to learn.
                            The information is available in any library and in many places on
                            the internet. I am self taught when it comes to physics,
                            electrical, mechanical & chemical engineering. My degrees are in
                            computing and Information Technology. But that doesn't stop me from
                            acquiring the knowledge I need to assist me in my chosen hobby.
                            Bottom line is, if you have a desire to learn, and a capable brain,
                            then the sky's the limit. Age is no barrier.

                            Side note for Riku: There are formulae for working out HETP.
                            They're called McCabe-Theile Diagrams, phase diagrams, and for the
                            lazy ones, computer simulations such as HYSIS . But you need to get
                            a lot more theory & prac under your belt (distillation-wise) before
                            you tackle that level. The 'net is your fingertip library. ;-)


                            I'm sorry if i am really slow with catching on to some of
                            > the theory here, but thats why i'm in the "new distillers" forum,
                            and
                            > i really appreciate all of your help.


                            .......Look on Tony's homedistiller.org homesite (homepage of this
                            group). That will give you a jump-start to the theory.



                            Someday, i want you all to be
                            > able to look back at me and say, "my god, what have we done!"
                            >
                            > -Tyler
                            >


                            Slainte!
                            regards Harry
                          • gff_stwrt
                            ... snip ... snip ... Hi, tyler, One of the best ways of learning is to ask the right questions of the right people. This is really interesting stuff, and
                            Message 13 of 13 , Nov 1, 2006
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                              --- In new_distillers@yahoogroups.com, "tyler_97355" <kd7enm@...> wrote:
                              >
                              > ok, so a 2" column "flooding" around 3kw is like my 1/2"
                              > liebig "choking" at 1.5kw when i tried to us it as a verticle reflux

                              snip
                              >
                              > I do wonder, how does one aquire this knowledge? >
                              snip
                              > -Tyler
                              >

                              Hi, tyler,
                              One of the best ways of learning is to ask the right questions of the
                              right people.

                              This is really interesting stuff, and thanks to you and the people who
                              have replied to your questions we are getting a different perspective
                              on theory and that's really good, too.
                              Thanks

                              The Baker
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