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Vacuum Assisted Distillation

TheMechWarriorTheMechWarrior
edited November 2015 in General

Does anyone have experience using vacuum with their stills?

I'm looking at trying to avoid the footprint etc associated with a steam boiler and think a decent vacuum pump in conjunction with a domestic high temp instant gas hot water system could be a nice easy way to achieve this. The instant gas hot water system is more than enough to meet my mash and cleaning needs.

Commercially available Ex rated electrical heating elements start at around $25k for 24kW plus all the Ex costs associated with the install inside the hazardous zone.

Thinking I could have the Ex rated vacuum pump and hot water service outside of the distillation space.

Cheers,

Mech.

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Comments

  • SunshineSunshine

    we have been on a seminar with Prof. Gössinger at the Agricultural University of Klosterneuburg about vacuum distillation spirits. The conclusion was, after a lot of tastings, that this kind of distillation is not helping the flavor - at least not for all kinds of spirits. The apricot brandy, that we tested was kind of dull compared to the same brandy distilled without vacuum - this one was bright and elegant. The products were made of the same mash. But as I recall, the outcome is different for different products.

    Prof. Gössinger does the research on this for years now and he reads on many conventions, also in the US. If you ever get a chance of attending, do so. It is very interesting.

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

  • grim

    You only need 24kw?

  • grim
    edited November 2015

    At that scale, why not a smaller electric steam boiler. Out here in the states Sussman is a popular brand, but out in your neck it looks like Simons? VS150? I even see some used ones online, looks like they are used in many laundry/ironing shops.

    Vacuum batch distillation not so cut and dry, you have a ton more hidden costs than you probably realize. For the 24k that elements cost, you can do a boiler cheaper, especially if you find a unit used. Wiring the boiler is more trivial than the elements.

  • DocPorter

    What you save in heating cost you pay for in chilling.

    Plus the additional cost of vacuum.

    The only use for vacuum distillation I see is to extract delicate botanical when making a gin. Maybe also breaking the azeotrope when making Vodka, but I can't find much solid data on this for Vodka production and how it impacts taste. I can only find info on fuel ethanol.

  • CothermanDistilling

    If someone ever gets a rotovap going good and can do a writeup on how to fully outfit one for our kind of distillation from readily available units and accessories, I would appreciate it...

  • grim

    The challenge I see with the rotovap setup is you need to make cuts blind with that cow.

  • TheMechWarriorTheMechWarrior

    24kW was for my baby still. The bigger still requires twice as much but as soon as I received the quote for 24kW of electrical heating I jumped. I've received a quote for a VS600 200kW gas fired boiler from Simons for $17k but was holding off to ensure I'd explored all options before adding more equipment to my current overcrowded location.

    I figured that with my instant gas system if I could use the vacuum system to ensure the 85oC water would be sufficient for my distilling needs then I'd be able to get by at my current location without the need to add a boiler or anything else more complicated.

    But basically, I could achieve the same result by placing an electrical heating system much like a rims outside my hazardous zone and using a pump to circulate the heating medium through the still jacket and back out to the heater.

  • grim
    edited December 2015

    Pulling a vacuum on a larger batch scale is going to require a pressure vessel, in my neck of the woods that opens up the door to a number of additional requirements, like an ASME tank manufactured for vacuum. This would cost far more than the steam.

    I believe full vacuum is equivalent to a 150psi rating, but not an engineer so don't quote me.

    If you are working with authorities who are sticklers for detail, this may also apply to your plumbing and receiving vessels as well (if you are cutting blind) or you'll need an explosion proof peristaltic to extract from a receiving vessel under vacuum (ala @Telluride).

  • TheMechWarriorTheMechWarrior

    Yeah, good points @grim. I really need to get the ball rolling on the steam boiler ASAP just wanted to be sure before I committed.

  • DocPorter
    edited December 2015

    @grim, from my experience a full vacuum pressure vessel is equivalent to about a 65 PSIG rating. Depends on vessel size etc. but that's what I've seen.

    A nearby distillery (Durham Distillery) is run by chemist. He uses a rotovap for some of his botanicals for their gin (which is really good). I'll ask him about making cuts next time I see him.

    image

    image.jpg
    600 x 800 - 65K
  • grim
    edited December 2015

    You just don't want this to happen...

    https://www.youtube.com/watch?v=oqwA-TqUC-w

  • TellurideTelluride

    Vacuum does not affect the amount of power needed to distill, in fact you need more power in the form of chilling. @DocPorter your chemist neighbor does not make cuts, he is probably loading that up with neutral that is already removed of heads and tails. Square one vodka uses vacuum distillation, nothing better nor worse.

  • TheMechWarriorTheMechWarrior

    @grim In recent memory I've seen a 100kL and a 22kL tank do the same.

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