Distilling very weak Wash

edited January 31 in Usage

I'm wanting to distill a very weak beer 2-3% in a 12" 16 Plate column still with a 1000L bain-marie boiler but could do with some help on still temperatures.

I would love to heat my still with our wood chip boiler which can only get up to 90°C and from what I've been reading to get ethanol out of a 2-3% wash I would need to be up at 98°C or so to be able to get it all out?

If I do need the extra few degrees I was hoping I could fit electric elements either inside the still itself or in the bain-marie sump and close my boiler off and allow the elements to heat it the rest of the way.

I am looking into ways of increasing my wash % but I don't want to add anymore sugars as this will take away from what I'm aiming to do.

Any advice would be greatly appreciated.

Comments

  • edited January 31

    Got any pics? How do you currently run your BM? What heating medium do you use? Does your system have a PRV? Is your BM rated for low pressure?

    At 1 bar you should be able to achieve 120C jacket temps.

    StillDragon North America - Your StillDragon® Distributor for North America

  • edited January 31

    Robin, you do not have the boiler yet - right?

    the question for me would be why you don't get more ABV. What are you distilling, what do you do with the wash? Why does your woodchip boiler only make 90° water? We have seen distilleries who use an extra boiler for the hot water, but usually they have no problem producing boiling water. Sorry for my questions.

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

  • Low alcohol runs l like that are almost not worth it with a batch still...

    Even with direct electric heat, which is much better near boiling temps than bain marie, I turn away 3-4.5% wash due to the cost of electricity and labor.. not worth it to get 3 proof gallons out of 100 gallons of wash...

    side note: I think a continuous would shine in that case... (said as I eye my 8" test rig and my 17' long piece of 4" SS tube I have standing vertical in the distillery waiting to be worked on)...

  • Agree that the continuous styled feed would allow for faster feed stock heat up with less energy,,,providing you can account for heat loss.

    StillDragon North America - Your StillDragon® Distributor for North America

  • edited February 2

    At the moment I dont have a Still but I do have our 300KW boiler which is used to supply the houses and cheese making . The boiler can go up to 95C Max temperature.

    We are looking at fermenting Whey left over from our cheese making process which gives a very low % Beer as there is not enough sugar in it to get any higher and I dont want to add anything else to it as it will take away from the reason we are using it.

    I did think about a continuous design, is it possible to adapt one of StillDragon's stills to do this?

  • edited February 2

    Boil the whey wash prior to fermentation to concentrate it and increase sugar to reasonable levels.

    Also explore vacuum evaporation.

    I believe this is how others are doing it.

    There may be a possibility to use reverse osmosis to concentrate and remove water.

  • We are looking at RO but it's very expensive do looking at alternatives.

  • Do you happen to have an anaerobic digester on site? Typically these are used with gensets to pump electricity into the grid, but the heat from cooling the engines on the gensets is often used for heating either through radiant heat or heat pumps.

  • No we do no have a Anaerobic Digester.

    Could someone point me in the right direction for sizing and designing a Continuous still design?

    Quite confident doing the Fabrication work myself once its been designed.

    I guess in the case of Continuous still it would be better stocking up on wash and doing 1 or 2 larger runs per week?

  • Seriously you must be able to boil down to 100 degres C otherwise your losses in alkohol will be enormous. Also consider you need a temperatur difference over the steam / water jacket to drive the process. You will need approx need to reach 110 degre C steam or water. If the system cannot take an overpressure 120 degre C water is 2 atmospheres (1 over ambient) otherwise you will need to use an oil as heating media or lower the pressure in the boiler artificiell.

  • You should use a lactose hydrolysing enzyme eg: lactase, beta-galactosidase This would bring you to a reasonable wash for distilling but you have to hold at 135 F for a while for it to work.

  • Ive come up with this design for heating the stills which should work well.

    As heating is not a problem now, Is there any recommendations on my still design? is a standard ish 16plate column still alone going to distill the weak beer or will I need to have a stripping still first?

    Many thanks

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  • edited April 4

    Also consider that you could use an efficient heat exchanger to directly heat the wash going into the still. It's fairly plausible that you could find a heat exchanger with higher efficiency than the still heat transfer area provides, and likely reduce the heat-up time. Ideal ideal scenario, is that you use a fill speed that approaches your 92c heating water temperature, and that fill time is less than the heat up time in your design. You'd be eliminating one entire heat-transfer stage by directly heating the wash.

  • @grim said: Also consider that you could use an efficient heat exchanger to directly heat the wash going into the still. It's fairly plausible that you could find a heat exchanger with higher efficiency than the still heat transfer area provides, and likely reduce the heat-up time. Ideal ideal scenario, is that you use a fill speed that approaches your 92c heating water temperature, and that fill time is less than the heat up time in your design. You'd be eliminating one entire heat-transfer stage by directly heating the wash.

    Hi Grim yes I had thought about doing this as well to help speed things up.

    What would our Ideal Temperature be for the pre heated wash be?

  • Your wash output temperature is going to be a function of heat exchanger size, efficiency, and flow rate.

    The 92c is interesting, but not as relevant as knowing the BTU output of the woodchip boiler. Do you know how many BTUs can be generated? If so, it's going to be pretty easy to determine the flow rate and output temperature to load the still.

    We're talking about liquid wash, minimal or no solids correct?

  • You get what I'm saying though.

    You proposed:

    Fire -> Water -> Water -> Wash

    I am saying that this is more efficient:

    Fire -> Water -> Wash

    Because you can optimize the water -> wash heat transfer in a way that's faster than the still wall, not to mention you eliminate an entire heat transfer stage.

  • By that do you mean this?
    What would be the maximum temperature the Wash needs to reach?

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  • edited April 5

    No.

    When you fill your still, you'll be filling it from your fermenter, through the heat exchanger, in to the still. You'll need to adjust the flow-rate such that your output temperature from the heat exchanger is close to 92c. What flow rate and how long will it take to fill? That's going to depend on how many BTU you can generate.

  • grim your one smart cookie , border line genius . im thinking by eliminating the one heat transfer the speed and efficiently would close to double . we find that heating anything with our hydronic boiler is a very passive heat and time is always the factor . tim

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