My first electric keg still with thump keg

[Danespirit]

Hey Moose...cool you got it running..
I run a cheap SCR from E-bay too..
Mine is only 3,8 KW..it's enough for my mind blowing 2 KW element.. (after all i am stilling in my bathroom).
I can tell you, insulating your boiler etc., will be the best you have done yet..
The heatup time reduces substantionally, the rig runs more stable...the electric bill let alone...
As i am a bit short of time now, the wooden casing with foam insulation has to wait..
As for now i am using a old towel beneath the bottom and one to wrap around the boiler, works well for my little milkcan boiler.
Seems like some in here don't insulate the riser and pipe going into the thumper, i would do so and let the takeoff be without.
This can be done with some of this insulation used for hot waterpipes, it's a foam molded to a shell and should be cheap to buy.
I use it for my column on my CCVM rig.

insulation.jpg (3.65 KiB) Viewed 1061 times

[Usge]

Pipe/tube diameter vs vapor speed/flow.
The amount of vapor "volume" you have is determined by how much heat you are putting into your pot (still charge). If you put that same amount of heat/ vapor through a larger pipe...it's velocity will be slower. The smaller the tube/pipe...will still flow the same amount of volume of vapor as pushed by the heat behind it....it will just be moving faster, or have more velocity.

Optimally, as the vapor travels along/cools...it starts to fall out and requires less "space" towards the condensing end than you might want or need towards the front end of things. So, a "taper" has long been thought to be the optimal design...to keep an even flow/velocity as the vapor travels from one end...to ultimately be condensed at the other for a smooth running still. This is inherent in the traditional designs of whiskey potstills as well as older "alembic" gooseneck designs.

When you neck things down directly from 1 or 2" down to 1/2" .....you are not decreasing the volume of vapor...you are increasing the speed of the vapor at that point....to varying degrees depending upon whether you are doing it closer to the front end of the still...or the backend/condensing side where the vapor is already starting to collapse or fall out.

[MooseKnuckle]

Now that you mention the way you insulate, I may give that a shot for the time being, Danespirit. I was using an old sweater just to test out with my old 1300w induction and pot. It did improve things, so I may actually just do that and see how it goes, then figure something out afterwards. Not sure I want a wood and foam setup as it makes any kind of access I may need to my fittings a bit of a PITA. I was thinking about the foil type, but may figure something else out as long as it's removable. I do have a 5500w element and 10000w SCR so it may not really need it but what the hell faster and same resulting product is not something I'm going to complain about.

And Usge, I do realize that the step downs are a bit blunt, but my intention with the step down from 2" to 1" was simply to adapt to the keg's existing fitting. I figure 1" is suitable for the boiler to thump, and since there is a fair amount of condensing going on in the thump, I figured 1/2" would be sufficient for that as well. I do not intend to run it all out except maybe for stripping runs as I was very impressed with the speed of my alcohol cleaning run when I got bored towards the end and cranked it up and watched it pour.

Surprisingly, the little 1/2" condenser kept up. This is probably due to the thump decreasing temp by a fair amount, but if the vapour speed does cause a problem, like say, not being able to knock down the vapours on a full blast stripping run, then I will simply turn down the element a bit. Not to knock the advice, I find it as valuable as any, but I made my boiler with a keg for one reason and that is the ability to make another head (or a bunch of them) for it down the road. If I get bored of this one than the next one just may follow the taper you speak of.

It was simply a matter of all the materials I needed to put this thing together were in stock at Rona and for the tapered pipe going towards my thump, I couldn't justify buying a whole sheet of copper when I don't even know where to get one. I've seen some very impressive designs and definitely have an interest in building more afterwards but this was a basic boiler and thump I wanted to get done and start using, and I think it will be more than sufficient for me to use while I wrap my mind around whatever comes next. If my girl knew what I spent on this thing even without a sheet of copper...

[Danespirit]

Pipe/tube diameter vs vapor speed/flow.
The amount of vapor "volume" you have is determined by how much heat you are putting into your pot (still charge). If you put that same amount of heat/ vapor through a larger pipe...it's velocity will be slower. The smaller the tube/pipe...will still flow the same amount of volume of vapor as pushed by the heat behind it....it will just be moving faster, or have more velocity.

Optimally, as the vapor travels along/cools...it starts to fall out and requires less "space" towards the condensing end than you might want or need towards the front end of things. So, a "taper" has long been thought to be the optimal design...to keep an even flow/velocity as the vapor travels from one end...to ultimately be condensed at the other for a smooth running still. This is inherent in the traditional designs of whiskey potstills as well as older "alembic" gooseneck designs.

When you neck things down directly from 1 or 2" down to 1/2" .....you are not decreasing the volume of vapor...you are increasing the speed of the vapor at that point....to varying degrees depending upon whether you are doing it closer to the front end of the still...or the backend/condensing side where the vapor is already starting to collapse or fall out.

+1 Usge...
Vaporspeed relates directly to Reynoldsnumbers. The speed determines wheter you have laminar flow or turbulent flow.
This is especially important when designing a refluxcolumn, say the takeoff of a VM still.
Moose...the wood and foam insulation, was only meant to do with my still..
It would be somewhat impractical as you have a setup with a fullsized keg.
Rocking around with that kind of weight, you should probably be green and about 2,50 M high...

[MooseKnuckle]

FINALLY!!!! One 15.5ish gallon rum wash is on the go. Just about filled up the keg, then put the rest in the thump basically up to the first bump in the wall. Took two full wine bottles before collecting to drink, about 750mL each. Very excessive for foreshots, but I figure, first drinkable run.... Why not be cautious.

If I decide to add back in the second bottle after a taste or two, whatever. But basically got the 1500mL then collected 2 1 gallon jugs as my hearts, from around 76% down to about 59%, it sat at 75-ish for a while, something I didn't notice so much of with the old still and small thump. The next rum wash will be collected more or less 85-55% depending on taste/smell, just wanted to run a little extra through the first run before collecting to drink.

Gonna use some of that dunder to start the next rum ferment, and hopefully tomorrow get off work early enough to come do the whiskey mash and set up another on the backset. Girlfirend's actually been patient with my cleaning runs and distilling instead of complaining the whole time... Possibly something to do with not spending an entire day just to get a little bottle...

[MooseKnuckle]

Well when I took it all apart and had a look, apparently I ran my thumper to the holes in my pipe. So I guess charge it a little more next time. Which is good because next time is going to be the whiskey where I put the wet grains in the thump and the liquid in the boiler. Anyway definitely better than overflowing it into the condenser that wouldn't be such an easy fix. I basically charged the thump with wash up to the first rim which is 1/3 full.

I would assume that since it held pretty steady for a while at 73-75% that this only boiled out after my hearts and therefore really doesn't matter, but this gives me the confidence to throw a load of wash in there with the grains for the whiskey maybe half or 2/3 full. And if that boils off too by the time it's done than even better, I'll figure out a way to cool the thump like I did my small one on the last few runs I did with it. If not then I just need to find the sweet spot for a starting fill level and see how it goes.

This rum tastes much more like a Jamaican Rum than the last batch did, which is what I was going for. Heavier molasses flavour and a nice kick, but very smooth. And this is right after distilling! Should have enough to set aside three bottles, one white, one oaked, and one black, and still have plenty leftover unlike the old pot where I barely had enough to last until the next batch was done.

[MooseKnuckle]

One question as I was considering the insulation fairly soon. If I was to insulate the boiler and the pipes to the thump, would this make my thump more likely to run dry or less? I would assume it would make it more likely. Meaning that it probably isn't the greatest idea if even when I load my thump higher with wash to begin with, it still boils dry... If it doesn't, then I'd try it. Is this a good assumption or would it be more likely to fill it faster rather than boil it out?