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Kettle Heating

In our Cider plant upgrade we have the possibility to upgrade to steam.

Steam for hot water heating, CIP plant, keg plant and of course kettle heating for distilling.

The question goes around steam heating of the kettle.

The purist I am sure will insist on a bain-marie type kettle when using steam.

But what if one uses steam coils within the kettle for heating.

How quality negative is this ???

Suggestions ??

Comments

  • Steam heating internally v externally need not have any impact on quality whatsoever, your engineer designing your coil can see to that. My suggestion would be to not do it yourself unless you are familiar with the necessary engineering. Being a steam coil it naturally has to be welded by a certified welder. Other than that, go for it. A coil is a pretty cheap solution compared to a bain marie, you've just gotta stay on top of the cleaning.

    Cheers,

    Mech.

  • You can use steam coils, but have you thought of a calendria instead? Might be an easier option for when it comes to cleaning.

  • edited August 2016

    Consider that if we're talking about retrofitting a still boiler with steam coils, it will likely require that the still boiler be cut in half. Any decent fabricator is going to require the still disassembled and shipped to them for retrofit. No one is going to want to be doing this kind of work in-situ. While the concept of a coil might be inexpensive, the fabrication and installation is going to be pretty labor intensive (expensive). A coil with a decent amount of surface area is going to be relatively large within the still boiler body. The coil would need to be formed and attached to the support frame externally, and getting that inside, well, cut cut cut.

    Would probably be SIGNIFICANTLY less expensive to find an used stainless jacketed tank, and retrofitting the existing column to the new tank. Or sell the still, and buy a new one.

    If I absolutely had to make it work, and the wash didn't contain a high percentage of solids, I'd use a thermosiphon reboiler.

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  • Why can't it be screwed in? If you get me drift.

  • you can spend money on a steam coil that fits in a drum or tote... but unless you got it for $500 used, I would go to a SD steam or B-M boiler....

  • I talked to one of the engineers at one of the big IBC companies (Custom Metalcraft) about using their drop-in coil as the primary heating for a still boiler. They didn't recommend it, as the primary use of the coils is to increase temperature to reduce the viscosity of the liquid in the tote for draining purposes - like warming a thick liquid after it's been shipped across the country in the freezing cold, not really bringing the full contents to a boil. They suggested dimple jacket was more appropriate, as the surface area was greater.

  • Yeah, those guys make a good product... and a jacketed tote will always keep it's value if you get the funds to upgrade to something like a SD 1000L S-A

  • edited August 2016

    I am fortunate in that I specialise in Stainless Steel, its design, fabrication, welding etc.

    So basically I build as much as possible.

    To fit coils into a kettle provided that the manhole is large enough to get through is a piece of tackie.

    Regarding the coils, I build /produce these for our keg machines. Basically any length. The present ones are a 25mm OD and is from a 6m length. I use it in one of my small tanks that I keep the contents at about 81 to 85 deg C. Heat up time with low pressure steam for 125L is about 14 minutes.

    Regarding the Calandria I would have my reservations. Reason being whilst it is brilliant for brewing in a wort kettle, in a distilling kettle there is not as much product turn over / movement. i.e. it is not as voilent a boil. Yes we can crank the steam up for a big boil, but then surely this is quality negative with distilling ??

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  • edited August 2016

    If you can fab, build a u-tube bundle and insert it though the side using an 8 or 10 inch ansi/iso bolt flange.

    The steam heating piping does not need to be coil shaped.

    This way you can remove it for cleaning.

    Steam should feed to the top of the tube bundle, condensate drain off the bottom.

  • edited August 2016

    Do you already have the kettle or are you thinking of a new purchase?

    In the UK our immersion elements are a bit bigger with typically a 2" or 2.25" fitting but we have available element replacements which are a coil with the same fitting as the immersion element.

    They are actually for thermal transfer fluids, but the principle could be adapted to steam. They are a direct swap for the immersion element.

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  • Gotta be really careful with steam hammer on a coil like that, as there is no natural path for condensate to freely drain.

  • A differnet take on a kettle boiler regarding vapour volume above liquid level............

    Is or are there any negatives in having an excessive volume above liquid level and below column.

    For example say you have a 380L kettle, obviously that is the normal fill level but you will have an extra safety volume over and above this. For normal pressurised tanks, I always allow for a 25% safety.

    The only negative as I see it is ... extra material costs. So if you for the kettle went with an extra approx 50% safety above level, can one expect any negatives. ??

    Part of the thought is for future expansion where there is margin for extra volume.

  • richard, the boiler should be designed to allow for the volume of liquid when its expanded i.e. after heating, you'll need additional space above that to allow for foaming and some vapour head room.

    As I read it, your question is: is there a problem if the boiler has a very large amount of vapour headroom?

    Apart from extra material cost as you say, IMHO, you'll likely get slightly more passive reflux.

    Is it a problem? I don't think so - consider the fact you can partially fill a boiler (of any volume) and continue to run with no problems (assuming you keep the elements covered if you use immersion elements).

    Is it worth buying a boiler that's 50% bigger now… you'll need to crunch the numbers but i don't think so. Why? I'd model my operation on a capacity then understand when sales need you to expand. at that point - you're likely to need a lot more than 50% extra capacity! The extra cost spent to buy the additional 50% during startup can be better used to buy other items / go to marketing / buy raw materials… Plan your expansion in other words. If you can afford it, but a 100% capacity increase up front (it won't cost that much more than 50% extra capacity) then you have options...

  • edited October 2017

    One issue to consider is that if the jacket height is significantly higher than the fill volume, you may cook solids onto the kettle walls, making cleaning more difficult. Foams will tend to caramelize and burn onto the sides when they rise to meet the hotter wall. I would also generally say wider is better than taller if you are going to oversize, and foaming tends to require the walls to have stability. In a taller narrower tank, a foam can likely build and rise faster and easier than in a shorter, fatter tank.

  • edited October 2017

    What's the typical oversize % on the StillDragon tanks anyway? I believe my 1000l is actually 1170l total volume. I've filled past the manway bottom lip before, somewhere close to 280-290 gallons (1060-1100l).

  • good points re the jacket & width @grim

  • I run into those problems making pasta every time. I always use the narrow pot, and end up with pots boiling over. Never learn that I should just fill the wide pot with less water.

  • @grim said: What's the typical oversize % on the StillDragon tanks anyway? I believe my 1000l is actually 1170l total volume. I've filled past the manway bottom lip before, somewhere close to 280-290 gallons (1060-1100l).

    I think it's different for each boiler, the 380L (non bain-marie) is actually 500L so that's quite a big difference.

  • If that's not a selling point, it should be.

  • I think I am at 100gal at or below the 'seam', where flat turns to dome...

  • edited October 2017

    Lots of those euro kettles are spec'ed at total volume, not typical fill. Meaning it's assumed that you will be ordering an oversized kettle sizing.

  • We always design and label the kettles for working volume and total volume.

    I don't have the ratio committed to memory. Do yew fellers want me to post up that info on the kettles?

    StillDragon North America - Your StillDragon® Distributor for North America

  • The Australian manufacturers also use total volume rather than working volume.

    It's not deceptive as such, but you need to know to ask the question rather than assume that common sense prevails.

    At StillDragon we think that working volume is the true volume you need to know, total volume not so much although it's stamped on the ID plates of each tank.

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

  • @punkin said: The Australian manufacturers also use total volume rather than working volume.

    It's not deceptive as such, but you need to know to ask the question rather than assume that common sense prevails.

    At StillDragon we think that working volume is the true volume you need to know, total volume not so much although it's stamped on the ID plates of each tank.

    What he said^^^

    StillDragon North America - Your StillDragon® Distributor for North America

  • Yeah exactly, that's why I said it should be a selling point. It's a feature really, especially if the headroom is larger on the smaller tanks.

  • edited October 2017

    We have found that some distilleries that are zoned in retail /flex space sometimes have issues with the volume of the kettle size. By that I mean the AHJ uses the total volume rather than working volume in order to disqualify the distiller from using a kettle that exceeds a "specific volume limit" for that municipality's limit for the above mentioned zoning. The AHJ essentially defaults to the total volume rather than working volume in a sort of CYA kind of manner.

    Always best to clear up those kinds of details before purchase,,, and calculating expected production volumes.

    StillDragon North America - Your StillDragon® Distributor for North America

  • In which case you pry it off and replace it with stick-on lettering?

  • Many thanks for the input

  • I'm using two 500L BM kettles. One is about 530L to the bottom of the manway "ferrule", and the other is about 605L.

    FWIW, I overfilled once and had liquid expand three plates into the column. I was crossing my fingers. Worked out fine and when the column stabilized, the liquid was below the bottom plate (22 plates).

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