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Stripping column on the 2" auxiliary port?

I have ordered the 500L bain marie kettle and the 8" pro cap column. I was wondering about putting a simple stripping column on one of the 2" auxiliary ports on top of the kettle. Since the kettle has not been made yet would it good to order it with a 3" or 4" port to allow for a larger diameter column? Or put a reducer on the 2" port to open it to a 3" or 4" column?

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Comments

  • You can put a lot of vapour through a 2" vapour path. I doubt you would need anything bigger to strip with. You just need a condenser that can cope with your power input.

    Regarding the bigger columns, some of the bigger commercial ones seem to manage with 2" vapour inputs even into 12" columns. There are posts on this topic in various places.

  • We have just recently recommended to exchange a 4" ferrule for an 8" one for mounting an 8" column because it just seems to make more sense to have the column port the same size as the column and for additional stability of the superstructure, though we clearly do not have enough info on the influence of such a venturi section. Having a reduction to half the diameter seems plausible, but 1/6? The big commercial columns look large from the outside, but with their single large bubble caps often only have a ~ 2" connection from one bubble section to the next (at least that's what I have seen myself on one of the typical German constructions).

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • That's a fair point - maintaining the total size of the vapour path through the plates to be the same as the entry into the column. There is some discussion ongoing about stability of the column (not physical but vapour/liquid stability) and it may make sense to add an orrifice plate, when using a full diameter column to boiler connection. Simple enough to do if it turns out to be needed.

    As for the stripping section you would probably use a lot of power before you actually get to a point where the vapour speed through a 2" tube was too high.

  • @Myles said: That's a fair point - maintaining the total size of the vapour path through the plates to be the same as the entry into the column. There is some discussion ongoing about stability of the column (not physical but vapour/liquid stability) and it may make sense to add an orrifice plate, when using a full diameter column to boiler connection. Simple enough to do if it turns out to be needed.

    Orifice plate could be as simple as a bubble cap plate without the bubble caps. I may try that one day soon but so far I've not seen the need. A back to back run with and without would be an interesting trial.

  • Vapor speed will reduce once the vapor has cleared the 2" port. There will be a little higher pressure on the boiler side of the 2" port due to the restriction, but the pressure and vapor speed will drop as the vapor enters the larger diameter column. Slower speed will allow more contact time in the condenser.

    But, that shouldn't matter with a stripper. The idea is just to blast it on through, increasing the ABV while carrying over as much flavor as possible, right? Stability with a stripper is just the product stream not huffing.

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  • edited February 2015

    Yes, going back to the OP there are two questions in one topic.

    Kettle size opening, increase it if for no other reason than ease of cleaning. However @SDeurope's comments all are valid regarding physical stability.

    For the stripper I don't think you need to go bigger than 2" on your 500 liter kettle. How you plumb it in might be interesting though. ;)

  • Hi @shindig. We have a 380L boiler with an 11 plate CD which we use for vodka and gin. For stripping we connect to one of the 2" ports (with a couple of 45deg bends) two half metre 2" pipes, then two 90deg bends, then a short section of pipe leading to a 3" product condenser. Works fine, we can run at about 17kw/20 liters per hour. You do have to blank off the column which we do after the dephleg. Easy!

  • @Grip said: You do have to blank off the column which we do after the dephleg. Easy!

    I'm wondering if it makes any difference if blanking off at the top of the column or simply below the product condenser (before the surge breaker), which would even be easier to handle.

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • Thanks @Grip! Can you post a pic of the setup next time you are stripping?

  • @grip - whattya think about this:

    the 2" pipe straight up from the boiler along the side of the CD... the CD has the normal dephleg and u-bend, then a 2" three way valve placed so that the strip port is on the bottom, the spirit port is on the top, and the outlet is on the side....

  • Hmm! @CothermanDistilling I'd need 2 x product condensers for that wouldn't I? As it is I change the configuration for stripping, vodka, gin so it's no problem to place the 2" blanking plate just after the u-bend on the dephleg.

    @shindig It is my intention to take photos of each of the three configurations to put on the distillery wall for every here to refer to. I'll post copies of these when they're done.

  • @Grip I think the intention was 1 condenser with a choice of inputs.

    Either from dephlegmator OR from strip branch. :D

  • ^^^ what he said ;-)

    Oh, and make sure the valve is implemented so that it cannot be set to a point that sealed off the boiler!

  • picture running your u-bend on top of your dephleg straight down to the boiler 2" port... now, at the top, interrupt that pipe with the straight section of the 3-way valve... the 3rd port(common port) comes out the side, takes a 90 down, and into the condenser...

    want a more balanced look? have the port go into a larger u-bend around to the condenser that uses the other 2" port as a mounting surface.. use a 2" down pipe if using 2" condenser(s), use a 3" down pipe if using a 3" condenser.....

  • edited February 2015

    In my best Vinnie Barbarino voice, "I'm so confused!"

    Could someone draw a picture?

    I'm more like I am now than I was before.

  • edited February 2015

    @CothermanDistilling said: picture running your u-bend on top of your dephleg straight down to the boiler 2" port... now, at the top, interrupt that pipe with the straight section of the 3-way valve... the 3rd port(common port) comes out the side, takes a 90 down, and into the condenser...

    want a more balanced look? have the port go into a larger u-bend around to the condenser that uses the other 2" port as a mounting surface.. use a 2" down pipe if using 2" condenser(s), use a 3" down pipe if using a 3" condenser.....

    That is an absolutely top idea. I was thinking an eight inch three way TC valve at the column mount, but that will work very effectively for either a stripper or a GB4, much prettier and a hell of a lot cheaper.

    We'd only need to stock a 3" three way TC valve and a 2" model to service all the larger stills from 4" up. Probably need a flex pipe rather than a 180 is all.

    I'd draw it if i could Kapea but it would look like a 2 year old kid with crayons did it.

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  • instead of flex pipe, how about a slip-fit extension tube with a nut / compression fitting similar to that under a sink?

  • edited February 2015

    Followed everything up till this part:

    @CothermanDistilling said: want a more balanced look? have the port go into a larger u-bend around to the condenser that uses the other 2" port as a mounting surface.. use a 2" down pipe if using 2" condenser(s), use a 3" down pipe if using a 3" condenser.....

    I'm more like I am now than I was before.

  • edited February 2015

    Here you go, just a quick impression.

    image

    still option 1.jpg
    337 x 467 - 25K
  • edited February 2015

    Nice work @Myles!

    I think you might want some kind of check valve on the defleg side of the three way to avoid blowback into that side. Pressure will be higher on the stripper side due to head loss across the plates, unless the three way is closed with a perfect seal.

    I'm more like I am now than I was before.

  • @Myles - thanks so much for the drawing!

    @Kapea - please explain what yo mean by blowback...

    I think you will find that nothing more than few drops of vapor condensate will make it over the u-bend... there is way more passive heat loss in the unused dephleg and u-bend than can be overcome by vapor that is just rising, and not really flowing....

  • edited February 2015

    If it proves to be an issue just run a trickle through the reflux condensor. Why wouldn't the valve seal? They seal in my water line with no leakage and it has pressure.

    Thanks for the picture Myles, imagine it now with the valve much lower and with the GB4 coming off the valve.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • I suspect you would also fit a bend to the 2" port to shift the valve further out from the column. I just modified that drawing quickly to illustrate the concept.

  • If stripper vapor gets past the three way it will encounter lower pressure on the plated side. A check valve would stop vapor from flowing in that direction. I'm not sure of the internal geometry of the three way valve. It would not be an issue if it seals tight every time.

    Individual valves and a static T are a recipe for disaster if both sides are closed when the boiler is fired.

    I'm more like I am now than I was before.

  • @Kapea Yes that is a bad idea. I did once build a valved still for experimental purposes. It could do just what you described but it was backed up with a PSV in a bypass line around 1 of the valves. Not recommended practice though.

    Possibly not needed here though. In a strip configuration the pressure felt in the strip flow lines should be minimal. Just the back pressure caused by the condenser. The seals in a valve should cope with it OK.

  • Just specify good sealing 3-way valve that is implemented so that it cannot seal off the boiler...

  • edited February 2015

    Guys, it's no bad idea at all to build a valved still, but for safety purposes I strongly recommend using a safety pressure valve + gauge on the second 2" top auxiliary port, then I can not see anything speaking against the use of our 2" Tri-Clamp 3-Way Valve.

    I'm not completely sure right now but I think the recommended relief value was 1.5 bar. Any thoughts on that?

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • If the valve is aligned properly it can't close off the still, only have the vapour path going one way or the other.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • An L shaped (inside) ball valve?

    I'm more like I am now than I was before.

  • edited February 2015

    I'm looking at this and its making me drool..... Imagine this, the only difference being the condenser would go straight down and I would hook up to the 3 way valve with flexible TC pipe which will ensure I can still change my plates!!!. hmmm anyone know where I can get a fairly priced 3" 3-way sanitary ball valve? =)

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