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Re: Running too hot!

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  • Ed Barcik
    One of the best explanations I ve seen.
    Message 1 of 7 , Jun 30, 2011
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      One of the best explanations I've seen.

    • IZbraun
      Thank you Geoff, for a very detailed explanation.  It really help me!!   I’m sort of disappointed that I followed the bokakob design exactly (except the
      Message 2 of 7 , Jun 30, 2011
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        Thank you Geoff, for a very detailed explanation.  It really help me!!
         
        I’m sort of disappointed that I followed the bokakob design exactly (except the size of condensing coil) only to find the column is too short and/or too narrow. 
         
        Assuming I don’t want to start from scratch and re-build my column, what can I do to improve my results?  I will try to do a better job with my heat but I’m using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be substantial as it cycles on and off.
         
        I’ve also got some leftover 3/16” tubing so I’m going to try to make a new double coil (coil inside a coil) to see if that helps.  I’ve see a few photos online but it looks difficult to make.
         
        Thanks again for all your help
         
        IZbraun


        From: geoff burrows <jeffrey.burrows@...>
        To: Distillers@yahoogroups.com
        Sent: Wednesday, June 29, 2011 2:56 AM
        Subject: [Distillers] Re: Running too hot!

         
        Hi izbraun,
        I can see three areas were your problems might lie I think these are:-
        1.      Your Column diameter and length
        2.      Your heat source
        3.      And a fundamental misunderstanding of  how different liquids boil when mixed with other liquids and at what temperature they then boil. In our case ethanol/alcohol  and water at various temps
         
        Let’s deal with
        Number 1. 
        Your column diameter and height  is smaller than the usual 2” diameter x 1 metre long  (at least) of our hobby stills and because this 1½” is narrower the steam/ethanol mix tends to move faster up the column than in the 2” type columns and your reflux rate will be down because of the shorter column length. 
             So a lot of the data you have on these forums appertains to the 2” x 1 metre columns and thus rules out a lot of stuff that you would expect to happen in your still i.e. your take off rate, your condenser size which needs to knock down that steam/ethanol mix fast or you’ll be giving a bigger share to the angels.  This leads on to your next problem area your heat source
        Number 2
        Because you have a narrower and shorter column than usual you need to keep really good control of your flame and when you start your run just keep that flame on tick over.  
        Keep it low and slow it’s the way to go.  That way your condenser can knock the steam /ethanol mix down easier.  Using 3/16 copper tubing is good the bigger the condenser tubing the better the separation rate.  If you were to give your column an extension of another 24”  you would find you’d have a better behaving still.  A lot of the guys on here have 1½” columns but they are considerably longer than 24”.  Having such a short column will make your still harder to control and as one member once said it’ll be squirrel-ee which brings us to
        Number three
        Ethanol will near as dam it boil at 78C so with a longer column and good control of your heat source i.e.  low and slow  You’ll find you don’t  need to constantly keep adjusting the flame because it’ll get to 78C and stay there throughout the entire run. One of the guys on this forum has a chart of the different boil temps of the ethanol water mixes and they’ll probably supply it if you ask.
             In ethanol water mix the ethanol boils first i.e.  the column temp, with the correct heat input,  will rise to and sit at  78C and as long as your condenser keeps knocking it down it’ll stay at that temp as long as you have ethanol or alcohol in the wash when the temp starts to rise there’s less alcohol and you can make your cut early depending how clean or pure you want your ethanol
          Bear in mind this is the way I see things but hey I might be wrong and if so I will be put right never fear
        Geoff


      • GGB
        ... I will try to do a better job with my heat but I m using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be
        Message 3 of 7 , Jun 30, 2011
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          IZbraun wrote:
          >
          "I will try to do a better job with my heat but I'm using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be substantial as it cycles on and off."

          Hi, my first post here.

          This is what you need. http://www.graham-laming.com/bd/Immersion_Heater_controller.pdf

          I made one and the power outlet is continuously variable from 0 Watts to about 3kW. Output depends on how you build it. Works like a charm. Just plug it into the mains, and then the element into it.

          http://i121.photobucket.com/albums/o229/girlguidebiscuit/DSCF0614_small.jpg
          http://i121.photobucket.com/albums/o229/girlguidebiscuit/DSCF0611_small-1.jpg

          Paul
        • geoff burrows
          Hi IZbraun Comments in line for your email. You wrote:- I’m sort of disappointed that I followed the bokakob design exactly (except the size of condensing
          Message 4 of 7 , Jul 1, 2011
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            Hi IZbraun

            Comments in line for your email.

            You wrote:-

            I’m sort of disappointed that I followed the bokakob design exactly (except the size of condensing coil) only to find the column is too short and/or too narrow.  The Bokakob is a good still don’t knock it. You just need some minor improvements for your still to make it good again.  And when you feel confident with that you can always upgrade the Bokakob to a "Vapour Management Still" Google it.  The concept might be a bit hard for a beginner the grasp but if you want pure good clean Vodka  Vapour Management is your next logical step.  Your learning curve is steep as a beginner at the moment.  So get used to this "still" first then upgrade   

            Assuming I don’t want to start from scratch and re-build my column, what can I do to improve my results?  

                 If you have attached your column to the boiler and you have welded or silver soldered it to the lid then come up about 3” from the solder line and cut the column nice and squarely across and deburr it . 

                 Get two 1½” straight column connectors.  Slip one on to the column stub.  Now remember you might be restricted for column height i.e. ceiling etc.  So now calculate your overall height you want your still to be.  You need at least another 18 inches extra.  So cut 18 inches or as much as you can get away with from your new pipe.  Put this into the 1½” straight connector on the column stub.  Slip on the second connector and attach the still on top of that you now have one 18 inch column extension.  You can solder this if you please but I would use PTFE plumbers tape nice and flat around the column connector joins and you can dismantle it for easy storage.  

                 I will try to do a better job with my heat but I’m using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be substantial as it cycles on and off.  WARNING

            An alternative to buying a controller.  Only do the following if you feel confident with working with electric.  Take your hotplate apart you’ll find the live wire will go through a thermostat, (in one side of the thermostat and out the other) and  then into the 1500Watt element and back out to the negative.  If you bypass the thermostat and join the two wires, that will let the electric go straight into the 1500Watt element and you’ll get the full 1500 watts heat coming through constantly no cycling on and off.  I use an 850watt 240 volt AC flat out all the way through the run   

            I’ve also got some leftover 3/16” tubing so I’m going to try to make a new double coil (coil inside a coil) to see if that helps. I’ve see a few photos online but it looks difficult to make.

            What you’re talking about is called a double helix condenser and is hard to do with ¼ inch pipe,  3/16th  pipe is getting pretty small bore , your pump has got to overcome the smaller bore restriction and longer pipe length for the extra cooling needed.  What you need is a bigger surface area on the pipe and a double helix on ¼” tubing is bloody good cooling surfacing area and hard to beat.  think of it as a one off investment.

            I think “Pint o’ Shine” on artisian distiller one of our forum members makes these up ¼” double helix condensers and sells them at a reasonably price for what you get to your own specifications if you can’t manage to do it .  Put “Pint O’ Shine”  into the forum search and you’ll find him.  Here’s his bloody brilliant tutorial on making a condenser coil and is required reading/viewing if you're making a condenser coil  http://artisan-distiller.net/phpBB3/viewtopic.php?f=11&t=1689

            Geoff

            ----- Original Message -----
            From: IZbraun
            Sent: Thursday, June 30, 2011 9:56 PM
            Subject: Re: [Distillers] Re: Running too hot!

             

            Thank you Geoff, for a very detailed explanation.  It really help me!!
            I’m sort of disappointed that I followed the bokakob design exactly (except the size of condensing coil) only to find the column is too short and/or too narrow. 
            Assuming I don’t want to start from scratch and re-build my column, what can I do to improve my results?  I will try to do a better job with my heat but I’m using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be substantial as it cycles on and off.
            I’ve also got some leftover 3/16” tubing so I’m going to try to make a new double coil (coil inside a coil) to see if that helps.  I’ve see a few photos online but it looks difficult to make.
            Thanks again for all your help
            IZbraun


            From: geoff burrows <jeffrey.burrows@...>
            To: Distillers@yahoogroups.com
            Sent: Wednesday, June 29, 2011 2:56 AM
            Subject: [Distillers] Re: Running too hot!

             
            Hi izbraun,
            I can see three areas were your problems might lie I think these are:-
            1.      Your Column diameter and length
            2.      Your heat source
            3.      And a fundamental misunderstanding of  how different liquids boil when mixed with other liquids and at what temperature they then boil. In our case ethanol/alcohol  and water at various temps
             
            Let’s deal with
            Number 1. 
            Your column diameter and height  is smaller than the usual 2” diameter x 1 metre long  (at least) of our hobby stills and because this 1½” is narrower the steam/ethanol mix tends to move faster up the column than in the 2” type columns and your reflux rate will be down because of the shorter column length. 
                 So a lot of the data you have on these forums appertains to the 2” x 1 metre columns and thus rules out a lot of stuff that you would expect to happen in your still i.e. your take off rate, your condenser size which needs to knock down that steam/ethanol mix fast or you’ll be giving a bigger share to the angels.  This leads on to your next problem area your heat source
            Number 2
            Because you have a narrower and shorter column than usual you need to keep really good control of your flame and when you start your run just keep that flame on tick over.  
            Keep it low and slow it’s the way to go.  That way your condenser can knock the steam /ethanol mix down easier.  Using 3/16 copper tubing is good the bigger the condenser tubing the better the separation rate.  If you were to give your column an extension of another 24”  you would find you’d have a better behaving still.  A lot of the guys on here have 1½” columns but they are considerably longer than 24”.  Having such a short column will make your still harder to control and as one member once said it’ll be squirrel-ee which brings us to
            Number three
            Ethanol will near as dam it boil at 78C so with a longer column and good control of your heat source i.e.  low and slow  You’ll find you don’t  need to constantly keep adjusting the flame because it’ll get to 78C and stay there throughout the entire run. One of the guys on this forum has a chart of the different boil temps of the ethanol water mixes and they’ll probably supply it if you ask.
                 In ethanol water mix the ethanol boils first i.e.  the column temp, with the correct heat input,  will rise to and sit at  78C and as long as your condenser keeps knocking it down it’ll stay at that temp as long as you have ethanol or alcohol in the wash when the temp starts to rise there’s less alcohol and you can make your cut early depending how clean or pure you want your ethanol
              Bear in mind this is the way I see things but hey I might be wrong and if so I will be put right never fear
            Geoff


          • Harry
            All the good advice you ve been given so far is very useful to fix your problem. Building stills is not just a hit or miss affair. Everything is worked out
            Message 5 of 7 , Jul 1, 2011
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              All the good advice you've been given so far is very useful to fix your problem.

              Building stills is not just a 'hit or miss' affair. Everything is worked out to balance.

              One thing you need to know when building a fractioning still of any sort (eg bokakob) is the vapor speed. The power input and the column diameter determine the vapor speed up the column. This in turn governs the separating capability of your column, and thus the purity of your product.

              The maximum vapor speed is around 18" per second. There's calculations you can do here in the files...
              http://groups.yahoo.com/group/Distillers/files/Vapor_Speed_101-Mike_Nixon.htm

              Using Mike's figures, your 1.5" diameter column at the moment with 1500W power input is running at almost 39" per second; way too fast and hence your troubles. To bring your vapor speed down to 18" per second, you'll have to reduce your power input to 695W max, in which case you'll need a controller like was advised in an earlier reply.

              The only other way to fix it is to go to a bigger diameter column. A 2" diameter column @ 1500W input runs at almost 22" per second. To run a 2" column at 18" per second the power input needs to be about 1200W. Or you can use an un-shielded column and 1500W because the unshielded column will lose about 300W heat to the atmosphere.

              Ideal lengths for component separating capability are:
              1.5" Diam --- 2 metres
              2" Diam --- 1 metre

              So now you know the 'what' and the 'why' of the issue.

              HTH

              Slainte!
              regards Harry
              =================================


              --- In Distillers@yahoogroups.com, IZbraun <izbraun@...> wrote:
              >
              > Thank you Geoff, for a very detailed explanation.  It really help me!!
              >  
              > I’m sort of disappointed that I followed the bokakob design exactly (except the size of condensing coil) only to find the column is too short and/or too narrow. 
              >  
              > Assuming I don’t want to start from scratch and re-build my column, what can I do to improve my results?  I will try to do a better job with my heat but I’m using an electric commercial grade (1500 watt) hot plate so the temperature fluctuation can be substantial as it cycles on and off.
              >  
              > I’ve also got some leftover 3/16” tubing so I’m going to try to make a new double coil (coil inside a coil) to see if that helps.  I’ve see a few photos online but it looks difficult to make.
              >  
              > Thanks again for all your help
              >  
              > IZbraun
              >
              >
              > From: geoff burrows <jeffrey.burrows@...>
              > To: Distillers@yahoogroups.com
              > Sent: Wednesday, June 29, 2011 2:56 AM
              > Subject: [Distillers] Re: Running too hot!
              >
              >
              >  
              > Hi izbraun,
              > I can see three areas were your problems might lie I think these are:-
              > 1.      Your Column diameter and length
              > 2.      Your heat source
              > 3.      And a fundamental misunderstanding of  how different liquids boil when mixed with other liquids and at what temperature they then boil. In our case ethanol/alcohol  and water at various temps
              >  
              > Let’s deal with
              > Number 1. 
              > Your column diameter and height  is smaller than the usual 2” diameter x 1 metre long  (at least) of our hobby stills and because this 1½” is narrower the steam/ethanol mix tends to move faster up the column than in the 2” type columns and your reflux rate will be down because of the shorter column length. 
              >      So a lot of the data you have on these forums appertains to the 2” x 1 metre columns and thus rules out a lot of stuff that you would expect to happen in your still i.e. your take off rate, your condenser size which needs to knock down that steam/ethanol mix fast or you’ll be giving a bigger share to the angels.  This leads on to your next problem area your heat source
              > Number 2
              > Because you have a narrower and shorter column than usual you need to keep really good control of your flame and when you start your run just keep that flame on tick over.  
              > Keep it low and slow it’s the way to go.  That way your condenser can knock the steam /ethanol mix down easier.  Using 3/16 copper tubing is good the bigger the condenser tubing the better the separation rate.  If you were to give your column an extension of another 24”  you would find you’d have a better behaving still.  A lot of the guys on here have 1½” columns but they are considerably longer than 24”.  Having such a short column will make your still harder to control and as one member once said it’ll be squirrel-ee which brings us to
              > Number three
              > Ethanol will near as dam it boil at 78C so with a longer column and good control of your heat source i.e.  low and slow  You’ll find you don’t  need to constantly keep adjusting the flame because it’ll get to 78C and stay there throughout the entire run. One of the guys on this forum has a chart of the different boil temps of the ethanol water mixes and they’ll probably supply it if you ask.
              >      In ethanol water mix the ethanol boils first i.e.  the column temp, with the correct heat input,  will rise to and sit at  78C and as long as your condenser keeps knocking it down it’ll stay at that temp as long as you have ethanol or alcohol in the wash when the temp starts to rise there’s less alcohol and you can make your cut early depending how clean or pure you want your ethanol
              >   Bear in mind this is the way I see things but hey I might be wrong and if so I will be put right never fear
              > Geoff
              >
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