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Will a long tube act like a fractionating column?

  1. May 5, 2005 #1

    ShawnD

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    I'm making a distillation aparatus and I've hit a block. The steel wool I packed into the plastic tubing (acting as a fractionating column) is rusting incredibly fast. I obviously don't want to be drinking rust, so can I just take the wool out and use an extra long tube instead? I'm thinking that having a tube that is very long will cause the gas to condense at least a few times along the way to add a few more theoretical plates. Am I right to assume this, or do I really need some kind of wool packed into this thing?
     
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  3. May 5, 2005 #2

    GCT

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    I'm thinking...no. What makes you think that it would condense in the first place?
     
  4. May 5, 2005 #3

    ShawnD

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    Why would it condense any less than when steel wool is there?
     
  5. May 5, 2005 #4
    The point of a fractionating column is that you have a large surface area of a good thermal conductor to absorb the heat from the hot gas which causes it to condense. In the abscence of such a conductor, the gas will not lose heat, and thus will not condense
     
  6. May 5, 2005 #5

    ShawnD

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    But once the initial amount of gas heats the conductor to the same temperature as the gas, this no longer holds true. Fractionating columns make distillation a lot harder, so they're generally insulated anyway.
     
  7. May 5, 2005 #6

    GCT

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    Well, I think surface area is key here, and with the column by itself, I don't think that it'll be effective...my humble opinion.
     
  8. May 5, 2005 #7

    Bystander

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    Are you talking reflux column or condenser? You do understand that you don't care (within limits) what washes back into the boiler. Pack the reflux column with old sweat socks. You don't want to pack the condenser --- that's where you collect the product --- try to keep that clean.
     
  9. May 5, 2005 #8

    ShawnD

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    I had initially packed it at the end of the plastic tube (fractionating column) that is close to the copper tube (condenser). I guess that was a pretty stupid move. Packing at the end closer to the boiling pot would seem a lot more logical.

    Thanks guys.
     
  10. May 16, 2005 #9

    ShawnD

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    Just an update to this. I took the steel wool out and just went with the long tube. Using a long tube DOES work as a fractionating column.
    Just thought you guys would like to know incase you ever make a still.
     
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