Alternative Hybrid Configuration

Anyone got any thoughts on hybrid configurations regarding the position in the column of the packed section?

I'm tempted to move things around a little, have A torpedo at the bottom of my column, then a 2" 510mm packed section with an Ace/Baby CD on top with a few plates.

I can't see any reason why not, it will still produce a neutral spirt, I just can't decide if it will be an improvement, a step backwards or just give the same results as having packed section on top of the plates.

Any thoughts?

Comments

  • One way to find out.

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  • Yeah, I will have a go and find out, I'm thinking it could be an improvement, but it's just a theory in my head for now, I'll have a go with a sugar wash I've done a few times before so I've got something to compare it with.

  • I'd put the packed section on top. The plates will hold more liquid and don't separate as well. To my way of thinking this means less smearing at the start of the run and less wastage and the end. In the end, the difference is probably SFA though.

  • @jacksonbrown said: I'd put the packed section on top. The plates will hold more liquid and don't separate as well. To my way of thinking this means less smearing at the start of the run and less wastage and the end. In the end, the difference is probably SFA though.

    I agree.

    I also believe the plates at the bottom will help the system better cope with what will become unneeded heat at the top of the apparatus.

    StillDragon North America - Your StillDragon® Distributor for North America

  • I also think packed section at the top so you feed it with enriched vapour.

  • Everything that I have read leans toward packing above plates but I have no experience to back that up.

  • @Smaug said: ...will help the system better cope with what will become unneeded heat at the top of the apparatus.

    I don't understand what you mean with the coping or the unneeded heat, could you detail it a bit better?

    @crozdog said: I also think packed section at the top so you feed it with enriched vapour.

    or plate section on top so you feed it with enriched vapour. I'm not sure what the logic/difference is there either????

  • edited May 2015

    It takes more heat to render alcohol out of a 7 or 10% kettle charge than it does to effect liquid to vapor phase change that occurs at the top of an enriched apparatus. Yet the heat that is generated has to go somewhere.

    That heat in the kettle (bottom) is way more than is what is needed at the top of the apparatus.

    The base of a packed column that is connected to the kettle has to basically take the brunt of the heat. The returning droplets on the packing are small compared to the larger liquid beds on the plate. The first job of the liquid bed is to condense incoming vapor. And so one could regard the liquid bed as a heat exchanger. And because the liquid beds are larger on plates than any droplets found on structured packing, it is logical that they have more capacitance to cope or absorb more heat. Thus sufficiently cooling the vapor that enters the packed section and as such will allow more packing at the base of the packed section to behave like the packing at the top,,,,,, where the magic happens.

    If I'm lucky, maybe @minime will chime and share his experience regarding this behavior?

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  • I still don't follow most of that.

    The heat exchange between vapour and liquid through wet, random packing is going to be much more efficient than a bubble through 1/2" of liquid. It's about surface area.

    Also, the amount of heat that goes in to the bottom of a column should be pretty much the same as what comes out the top it. It just gets mixed up a bit between sensible and latent. 1000W heat in the bottom and the coolant will have to take the same away at the top (minus loses) regardless of your column type, no?

    The thing that changes is the volume of vapour that can be produced, not the amount of heat. When we're at boiling points all that heat goes into phase change not temp change. I don't think the overall gradient from top to bottom would change much with one way over the other.

    Are you saying the total number of HETP would change?

    ???

  • I was thinking it might make the packed section more efficient, with a few plates above it, the top of the section can't be "over cooled" by the RC

    I've read in the past somewhere if you over cool the top of a packed section you can effectively loose some theoretical plates, I also beleve the theoretical plates are closer together at the top of a packed section.

    I'll have my torpedo below it to take the brunt from the boiler and provide a steady vapour flow into the section and a few plates above to provide a steady reflux return, this will be an interesting experiment :-)

  • You'd just be cooling the liquid in the plates instead.

    I think the processes your describing are exactly the same both plates as for packing. They're both doing the same things via the same mechanisms. The level of vapour/liquid interaction is just a bit denser in the packing due to more surface area.

    It will be interesting though, keep us informed.

    I don't think you'll see much difference to be honest and any you do see won't really mean much if you didn't have perfect control of all the other variables.

    This is the problem with most circumstantial testing that goes on the forums.

    Accurate reflux ratios and boiler charges make a massive difference and they rarely happen. Same as packing density etc etc. It's really hard to do side by side comparisons on your own gear let alone comparing to some guy on the net.

    Even the double column that was put up here a while back would have suffered from different pressure drop over each column making any comparison pointless.

  • in relation to my "enriched vapour" comment:

    running through a few plates will increase the abv% at the top plate. on a dash 4 I can get 90% easily directly off wash. I consider the product at the top plate to be "enriched vapour" - as compared to whatever comes out the top of the boiler is it a lot higher in abv. by feeding this higher abv into your packed section, I believe the packed section then only needs to work within a few % points to purify the spirit as much as possible (high reflux ratio) rather than the packed section having to work hard to get the low abv boiler output all the way up to 95%.

    I simply do not see that after going through a heap of packing that adding a few plates on top will do much if anything to improve the output - but as explained doing it the other way around IMHO will.

    to paraphrase @punkin - try both & report back

  • I'm thinking the proof of the pudding will be in the eating :-)

    I'll have to make two runs with the packing and plates reversed in the second run, using half of the same wash/low wine for each, and try to keep the boiler power and cooling the same for both, or at least as close as I can.

    Then sample the finished product to see if one batch tastes any cleaner than the other.

  • @punkin said: One way to find out.

    I am with @punkin... try it and get back to us... then we can put this in the 'been there, done that' category and move on to something else, and point to this when someone new comes in and asks again in 6 months...

  • edited May 2015

    Has been done by reliable sources couple of years ago.

    Where does one think the SD hybrid config came from?

    No need to underestimate the skill level of the community at large.

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  • edited May 2015

    I've run three plates on top of 22" of lava, it was a while ago and memory is stuffed, but from what I remember, it acted like @crozdog commented. I remember the plates holding bugger all fluid, it ran strange, not as stable as the packing on top, just felt like it was struggling to get going, ABV was down a touch if I remember right. I've tried packing in the modular sections between each plate to, ran like a piece of crap!.

  • When I first started I used to pack below the plates, but it seemed that heat up took forever to get the plates loaded. Since I have stopped packing below the plates my heat up time has been cut to half.

  • Might not turn out to be a worthwhile experiment after all, I've got another 3 sections for the Baby CD waiting for me at the post office, this will give me 6 plates to play with :-)

    Does anyone agree that if I added a packed section within the Crystal Dragon end pieces, so it was 2 1/2 inch wide It would increase my potential collection rate over using the standard 510mm 2" section on top of the Baby CD?

    There's a famous master glass blower that I pass everyday on my way to work, I'm tempted to drop by with a section of the glass to see if he could make me one 500mm long with the same dismeter as the original glass sections.

    If that proves too expensive I migh look to see if I can find some copper pipe with a diameter that fits into the Baby CD special silicone gaskets.

  • edited May 2015

    @Anavrin said: There's a famous master glass blower that I pass everyday on my way to work, I'm tempted to drop by with a section of the glass to see if he could make me one 500mm long with the same dismeter as the original glass sections.

    We have a Crystal Packed Section in mind, based on the 2" sight tower with glass sections of 300 mm and 500 mm in length, though it will take some time till they are available because we just received a new resupply of items.

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

  • @SDeurope If I was you, I wouldn't bother using the 2" sight glass as a base for this idea, the 2.5" size used for the Baby CD offers much more flexibility and performance in terms of being able to mix plates and packed sections in one unit, it would be a much more commercially viable product, also with the increased product collection rate over a 2" version.

    Just need to get the price down of the 2.5" Baby CD to tri-clamp end plates, they're very expensive for someone who's budget is for a still of this size.

  • edited May 2015

    Something we will look into. A separate 2" sight tower as packed sections seemed to be more interesting than mixing plates and packed section in one 2.5" sight tower, and the 2" is cheaper of course because it's a standard item.

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

  • @SDeurope said: Something we will look into. A separate 2" sight tower as packed sections seemed to be more interesting than mixing plates and packed section in one 2.5" sight tower, and the 2" is cheaper of course because it's a standard item.

    @SDeurope not cheaper..... more cost effective in that size range as its not a custom product :D

    more effective terminology

  • And right you are, @FullySilenced! :))

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  • Non-native English speakers we are... :-B

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