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StillDragon Continuous Still

I've read though a few threads in this forum on continuous distillation and they've inspired me to design my version of a continuous still using primarily StillDragon parts for a micro/craft distillery. But first off, the purpose of the continuous still: to process a fermented mash @ 10% abv (void of solids) at a rate of ~150L/hr to a low wine abv greater than 90%. The ~90% low wines will be further processed in spirit run for a final neutral spirit >95% which can be used for vodkas, gins and other spirits.

A few thoughts:

  1. All the components are SD parts except for the custom fitting which I'm calling a take-off fitting. (Please ignore the parrot).
  2. The column is 4" and perf. plates or bubble cap/DC plates can be used. Of course perf. plates would be cheaper.
  3. The picture I'm showing here is the still being heated by direct steam. I really don't like the idea of direct steam because the steam will have to be food grade. Untreated municipal water going through your plant boiler can shorten the life of your boiler really quick. Thus I liked the idea of a reboiler and the plant boiler remaining closed looped. The schematic shown here does not show a reboiler (that's my next design).
  4. The feed pump is not shown. Also, I have yet to consider instrumentation and control (which is not my forte) for data logging and safety.

Anyway, here's my design and a rendering of the 4" take-off plate in front and iso views.

Thoughts?

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Comments

  • Put a take off plate after the dephlag, then install another dephlag, this take off will be product. Above the second dephlag is heads and fores. You can knock that down with a condensor, so you dont have stray vapors roaming around. For both dephlags you could use cold water for a better control of your reflux. What type of power do you have available for this?

  • edited April 2015

    The second column a rectification column? By the mid-column location of the drain - I take it you are trying to separate off heads as well? So not a continuous stripper?

    The second column reboiler duties could probably be easily handled by a 5kw element - this based on nothing but the potential vapor speed capacity of a 4" column.

  • @Telluride you're right about the additional dephleg to separate heads and hearts. I would subsequently cut the hearts to ~40% and run through a column still to achieve >95% neutral spirits. There would just be less cuts to make.

    Also,if you notice I have a dephleg at the bottom of the stripping column to endure the bottoms stay knocked down. The more that I think about it, that dephleg is probably unnecessary.

    In terms of of available power, I currently have a controller that powers two 5500 watt elements. I'll use these to generate steam and perform a test run. However, long term, if I were to set this up in a distillery and run "continuously" I would power the column with a reboiler (with steam from the plant boiler). I'm still researching reboilers and coming up with my own design based off the kettle type or thermosyphon.

    I would also have level control switches on the bottoms reservoirs that would shut the system down in the event of clogged drain lines.

  • edited April 2015

    @grim, the second column is a rectifying column. The first column is a stripping column. I am trying to separate the hearts. I think Tellurides comment about adding additional dephegs on the rectifying column can accomplish the goal of removing hearts.

    You said:

    The second column reboiler duties could probably be easily handled by a 5kw element.

    I was thinking that sufficient energy from the seam input fitting on the bottom of the stripping column would heat both columns, no?

    I'll also insulate both columns and the piping between each column to make the system more efficient.

  • What Telluride said... Another dephleg and condenser for the heads. Maybe even some plates/packing between if you have the room.

    Also drain from the rectifying column back to the stripping column, not to the drain. You'll be losing a lot of good stuff. There's a reason why columns are tall

    I agree you should remove the bottom dephleg. You want it to be the hottest down there.

  • @DocPorter, thanks for the input.

    Good point concerning the drains. I think I will separate the drains from the two bottoms reservoirs. The bottoms reservoir from the stripping column should have a pretty low abv. Whereas the bottoms from the rectifying column will have a higher abv.

    I'll have give it some more thought in terms of sending the rectifying bottoms back to the sripping still becuase it seems that these molecules would eventually build up and would have to eventually be taken out. Maybe I can send the rectifying bottoms back to the mash and when a fermented batch is 80% complete, then send the rectifying bottoms to the drain. ~O)

  • This is pretty exiting. Are you the customer in NZ i shipped all the gear too that had the idea to do this? I often wonder how you are going with it if so.

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

  • Another thing on the product take off, you should be using some sort of bubble plate where it cannot drain back down, drains only into a collection vessel, everything that would get to that point should be hearts and heads, you dont want anything draining back into the column at that point. You can always put the columns on top of each other. Just one big heads up, this is gonna be slow, maybe a couple gallons of wash processed per hour.

  • I would also be looking to being able to get straight azeo out of this, its possible, if I were planning on redistilling everything, I would look into just a continuous stripper.

  • @punkin. No I'm not your customer from NZ. I purchase my SD products from smaug. B-)

  • @Telluride, concerning your point about azeo, if I'm going to assemble a continuous that can make the cuts I might as well make the rectifying column tall enough to produce azeo...good point. Just guessing, probably 16 plates on the rectifying side would work.

  • A follow up on this project. What were the final results.???

    You talked about a feed of 150 Lph and a final take of of +90% abv. Also the use of two heating elements ??

  • OK - way late to the party, but ...

    At 150l/hr & 10%ABV you'll need ~25kW to get product to the first plate. You could theoretically collect ~14kW of that in the dephleg/coolers/condenser but realistically not. So 11kW isn't enough.

    At that feed you'll be hitting ~0.365 mol/sec of vapor at the first plate, or 10l of vapor per second. So velocity in a 4" design is ~120cm/sec. I'm pretty sure you need a larger diameter for that (or a much slower rate).

  • edited June 2019

    Do you plan on running grain in?

    EDIT: Ah I see this is an old thread and at this point likely no outcome. The design is rife with issues.

    StillDragon North America - Your StillDragon® Distributor for North America

  • @stevea said: OK - way late to the party, but ...

    At 150l/hr & 10%ABV you'll need ~25kW to get product to the first plate. You could theoretically collect ~14kW of that in the dephleg/coolers/condenser but realistically not. So 11kW isn't enough.

    At that feed you'll be hitting ~0.365 mol/sec of vapor at the first plate, or 10l of vapor per second. So velocity in a 4" design is ~120cm/sec. I'm pretty sure you need a larger diameter for that (or a much slower rate).

    you would have to collect heat from bottoms as well as the PC. The bottoms have 5x the flow rate and higher delta-T, but no phase-change energy recovery.. still a LOT of energy, can be equal to the PC energy in the right circumstances.

  • StillDragon North America - Your StillDragon® Distributor for North America

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