05
Jun
11

Uh… Sort of forgot to say what I’m actually building…

It’s been gently brought to my attention that I haven’t really explained what the hell I’m up to. I kind of started writing that last post without considering the fact that not everyone has been rolling the design around in their head for the last year… I’m trying to create a very modular collection of parts that can assemble into a variety of different arrangements, but for now we’ll just look at the two extremes. The full reflux column and the pot still.

The column is going to look a little like this:

The full reflux column

Experienced distillers amongst you may be saying “um, wtf are you doing?”, so let me explain the design.

For a start, if I want to go commercial, I’ll need a good supply of neutral to experiment with, without having to spend a whole weekend to do a run to get it. So, an upgrade from 52mm (say a generous 2.5l/hr @aezotrope) to 103mm diameter column, which should do at least 8l/hr if I can get enough heat input to it. This will mean I spend less time making ethanol and more time crafting flavoured spirits.

A standard VM

Secondly, I want to try and build a new type of head on the still to see if some more control can be eeked out of the vapour management design. Currently, a VM relies on turbulence and ethanol density to get a vapour split between the overhead reflux condenser (which will return reflux back down the column) and the takeoff port, which leads to the product condenser. While this way of doing business has some serious advantages that I won’t go into right now (see this thread I wrote on home distiller to understand more), the big disadvantage to this is it’s very hard to run in low reflux operation – say for flavoured spirits. I want it to work differently.

Instead of  using a passive split, I want to force the vapour to split between two ports that resize in tandem – If I want to set reflux to 75%, the product should then be 50%. I also want to be able to completely shut down reflux and run as a tall columned pot still. The easy way to do this would be to have two valves. However, that would break a golden rule – never build a system that could allow the still to build pressure. It must always, always be open to the atmosphere.

So, I’m going to put a cross pipe through the column at the top with an aperture cut into it. A machined copper plate will slide along inside it to change the vapour split. It will have a teflon braid (safe with hot ethanol) seal around it. This should force a vapour split, and allow me to “dial in” a specific reflux ratio. This isn’t all my idea, I’ve had help from a lot of people, most notably Harry Jackson for the concept of a forced VM, and Airhill on Artisan-Distiller.net for brainstorming ideas of how to actually accomplish it.

An illustration of my splitting valve concept

Note that these illustrations don’t actually show all the pipes – the plumbing of the cooling and reflux circuits is excluded.

The split will control the flow between two types of shell and tube condenser. The reflux condenser will be a 4″ / 1/2″ shell and tube, heavily inspired by the Jackson Crossflow condenser.

The crossflow condenser as it is traditionally configured. This is a type of shell and tube condenser. Image credits to Samohon on homedistiller.org/forum

By mounting this offset instead of overhead, I can form a pool of distillate, which can be drawn off back to the column as reflux, or via a needle valve, as product takeoff via liquid management. This will allow me to bleed the heads components without letting them contaminate my product condenser.

The product condenser will be a 63mm & 13mm  ‘shotgun’ type of shell and tube condenser.

This is a standard configuration for a "shotgun" type shell and tube condenser. Image credits to Samohon on homedistiller.org/forum

If you look at the illustration of my design, you’ll see that the shotgun condenser is designed to be removed, and is also way, way overkill for a reflux product condenser. This is so that it can be reused as the condenser for the pot still.

The reason I’m getting away from liebigs and coils for cooling is simple – backpressure. I recirculate all my cooling water via a pump and a radiator, and the pump really struggles with the coils. shell and tube condensers by nature have a very wide water path, so you can get very good flow rates on a shitty pump.

The pot still head is going to be more simple, I’m not even going to bother drawing it up. a 90 bend at the top of the column, then a triclamp, then a 45, reduced into the shotgun condenser. The triclamp will allow me to set any output height, which is a huge quality of life improver when running a still – remember you can’t use a plastic funnel or anything like that to direct output, not ethanol safe. Here’s a mock up:

Just some parts thrown on the table to illustrate the pot still shape.

Initially, I’ll just be using a keg boiler. Longer term I think I’d like a small hot water cylinder. They’re all copper here, and about a 100-150L boiler with pre-installed elements and drains would be very convenient I think. Either that or I’ll look into getting a stainless boiler fabricated for me, or salvaged.

Hope that clears up what I’m up to.

Cheers.

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2 Responses to “Uh… Sort of forgot to say what I’m actually building…”


  1. November 8, 2011 at 7:23 pm

    Been awhile since you’ve posted, how is the still coming along? Is it complete?

    • November 8, 2011 at 7:31 pm

      Hey there,
      Yeah, winter is a hard time for me to get anything done (ski season), and I’ve also been upgrading my beer system which took a lot of my time. Thats over now, so I have been working on the still again. I’ve been shooting a lot of video of the construction as well. The pot still components aren’t very far off now, just need to solder up the heat exchanger and leak test it. the 50L boil is all welded up and set for electric power, but I’d still like to put a centre drain and adjustable legs on it. I’ve also got a bigger boiler in the works, about 130L, that’s more long term. The reflux column and especially the valve (well, only the valve, that’s pretty much all there is left to do) will take a bit of time though. I’d like to get it all done before christmas, though life might get in the way!
      Cheers.


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