CCVM build and questions about diameter

[Mixo]

Hey team,
Hope you're all fantastic.
Looking for help with a few questions. I'm planning the build for my first still and I've decided to go with a CCVM on a keg boiler.
Plan is: electric still using 2x 2400w elements (running on different circuits). I know a fitter and turner who hopefully can help me getting the boiler together, and maybe the column and condenser as well. Going modular, connecting everything possible by tri-clamps.
I am time poor so hoping to build a still that will run fast (without compromising quality of course!). I've done a lot of reading on this forum and via other sources, but I'm stuck on a few points that I can't quite seem to understand.

So, the main question I have is about speed, and how to get it: I have read that a larger diameter column will increase the distillation speed (though I've seen some people dispute this) but what I don't understand is how much of the column/still/condenser need to be the larger diameter.

- If I went 4'' column for speed, does the whole still and condenser need to be 4'' to get the benefit? Or can I just attach a 2'' product condenser to a 4'' column and still gain speed? Another way to ask this question: which parts of the below plan need to be thicker to gain speed? Just 1? 1-4? 1-2?

Plan - Copy.png

Bonus questions - Is 4800w enough to even run a 4'' still?
Does the thickness have a different effect when the still is in pot still mode vs reflux mode?
I don't know where to go to get 2nd hand copper pipe - do all metal scrap yards also resell?
Also, I have found a number of distilling stores selling 3600w elements. But wouldn't this exceed the capacity of most normal house circuits? Why are there so many listings for these elements when most houses can't run them?

I know this is a lot of questions all at once. Really appreciate any help you can provide - thanks!

[MattSmith]

2 x 2400w is plenty for a 4" still (it's what I run and on a spirit run the 2nd element is barely on). You need a 15 amp point to run a 3600w element. I use one for stripping (6000w total) and it was definitely faster than 4800w. Maybe try 4800w first and then see if you want more speed. I don't use the 3600w for spirit runs because its too much power to begin with and finding a power controller for one is hard.

I run a 4" packed column with 4" RC that reducers into a 3" PC. I wouldn't want it to be any slower (a spirit run is 12 hours from start to finish). Speed was part of the reason for the choice (I had a milk can already which has a 4" opening). I can't comment on if you can run a 2" as fast as a 4".

[RC Al]

With out getting technical, height is purity, width is speed.

Looking at a plated column, the same number of plates are required to hit a given purity, regardless of diameter. The vapour has to pass through 15-20 plates to make a neutral. The wider the column the more that passes through each step.

When you move over to a packed section, its more or less the same thing except they pick up a bit of height efficiency as you go up in width - provided you keep adding power.

On the hobby front we are wanting a 15-20x diameter height for neutral which limits us in width - 2m of 4" on a boiler with a reflux condenser as well is a lot to fit somewhere (not to mention the weight) and will involve a ladder... 3" is as big as you should need :whistle:

For a plater to make brown spirits, I run my 3 plate 4" at 2.5lph at most (usually closer to 2) the people i know with 6"ers run about double that, a big boiler helps.

Arguably only the column and reflux needs to be the rated size (maybe a slightly smaller RC in a pinch), but going less than half elsewhere (imho) can lead to issues, that said i have run my plater with a 1/2" id liebig, works, but a bit of a pita to run. I have read that you can cram 100 lph of vapour down a 2" tube and that many large commercial systems get by with 3/4-1" to move vapour around, you just need to slow it down with an expansion chamber before running it through a condenser.

PS Matt, get some more power if you can, 4800w isnt enough for a pure 4" packed column, you can't generate enough reflux to run that thing as fast as it could.

[RC Al]

Doh just re read and noticed you have 6 kw matt, use it all! Reflux back to the take off speed you want, see what happens @ 5-6 lph oh and add another big spool of packing lols

[Mixo]

Thanks RC, Matt - I reckon what I'll do is see what I can find in pipe for the column and RC, but aim for thicker than 2''. I'll bear in mind that I can have the PC be narrower than the main column, but I like the idea of keeping it at least 50% of the column. Now I just have to navigate finding 2nd hand pipe :think: