Hybrid VM Column / Pot still

[Stillbilly]

Hello, and thank you for any help (and patience) during my learning curve. I love this art and learning is half the fun. As soon as I think I know what I'm doing and what I want to build I find and learn about yet another process of stilling that leads me down another rabbit trail.. This site has me in a constant reflux which is great but it does Strip away some time.

I have a 2" x 10' copper pipe along with some fittings to make a VM Still with a liebig (3/4" over 1/2"). Planning on using my Blichmann pot boiler with a 1/2 barrel keg. My thinking was to build a VM still and use neutral spirts to make martini's and flavored cocktails, but I also like whiskey and think a not so pure strip would be nice. I might end up with both a pot and column still, but could a hybrid suffice?
Some questions running through my head.

Time: Is there much of any time advantage running a 16" pot still vs a 50" VM column still ? (using a 2" pipe on both) say a 10 gal batch 10% abv. (I will enjoy the time chillen and distillen though)
Water: My house uses a constant pressure well system and I don't want to run the well pump on/off for 6-7 hours on a VMs, so I think using a 3/8" snake in a large volume of cold water would be easy on the well and electricity - so the pot still wins in this area. (?)
Propane: Time is money / propane is a money burner. I also dont want to burn up 6 hours of propane on a VM column. Does that sound about right - for 10 gal on a 50" VM column? would it burn less running a pot still?

So would a 36" column on a VM still with the ability to shut off both condensers be an excellent pot still and average colunm still?

[Prairiepiss]

Build 2 separate stills. One pot and one VM.

The VM can't be ran without the reflux condenser running. You would loose all your alcohol vapors out the top of the column. And even if you blocked the vent. Having a valve on the output of a sealed still is a big safety no no. Potential bomb.

Use the pot still to do stripping runs and whiskey runs. Use the VM to run a collection of the stripped runs diluted to 40%. Look at getting a water holding tank and use a recirculation pump to run the condensers on the VM. Many examples around here.

[Stillbilly]

I will plan on building a dedicated VM still and add a pot n thumper later as it looks to be the way to go.
I finished wrapping a simple column condenser for my vm build.
Been searching on HD google but have not found the ideal distance to have the condenser above the take off branch. I heard having it too low can cause a problem.
Does 2x diameter above take off sound right? (which is what im doing with the packing below)

Also, will I regret not having it be able to tear down into a few pieces? space is not an issue but not sure how difficult they are to clean.
Just the condenser will come off, the rest would be all soldered. or I could just use teflon above the T and below the T.. ?



2" column, 44" packed, 2x2x2 T, 1" valve, 3/4 over 1/2" liebig x 40"
onto 15.5 gal keg using 2" ss ferrule

Thanks for any input,

[rad14701]

Stillbilly, I'd consider that distance more important with a T the same size as to column as opposed to a reduced T... 1 - 2 column diameters should get you in the ballpark... With the reduced T you are dealing more with accelerated vapor speeds whereas with a T the same size as the column you aren't...

[Stillbilly]

Thanks Rad,
I will have the coil 2 - 3" above take off. Yea, I may have a velocity issue with no reducer. I will run it and see and later add a washer if it has issues.

btw, I boiled up your All Bran Recipe this past Monday. It's still bubbling away. Im use to beer wort which is no where near as violent as this stuff! this yeast really knows how to party. planning on using half of this for a "cleaning" run.

chow-

[myles]

Thanks Rad,
I will have the coil 2 - 3" above take off. Yea, I may have a velocity issue with no reducer. I will run it and see and later add a washer if it has issues

With the conventional in-line reflux condenser design with the product vapour port at 90 degrees to the main vapour path, the main reason for the column restriction is to increase the vapour speed. This introduces turbulence in the vapour spliting chamber (the body of the T) and is an aid to getting a reasonable split in vapour paths. You might find that you can introduce sufficient turbulence with some sort of obstruction at the top of the column, below the T. Possibly a thermo port?

If you go down the route of fitting an orifice plate (washer) below the T, you might wish to also include one above the T. With your product valve wide open the theory is that the vapour splits in relationship with the cross sectional areas of the two ports out of the vapour splitting chamber. A lot of folks try to get this 50:50.

If you are concerned with such things, then the theoretical max product rate (with the valve wide open) is pre-determined by this split between vapour into the VM branch and into the reflux condenser. Although, I have never quite got my head round the impact of the bore size of the VM valve itself, and the placement of that valve? I just follow the 50:50 rule ( and ignore the reduced bore valve) and hope it works out OK.

[myles]

Sorry forgot to say that with that length of 2" tube you have plenty for a VM column and a pot still. You could use the same condenser on both, but I would reserve a bit of the 2" to make a pre-condenser. Wind yourself another coil to go inside the 2" tube and put it on the pot still just above your product condenser.

You will probably only need to use it when you are doing a strip run. If you build your condenser so it is the correct size to cope with a spirit run, then it might not have enough cooling capacity for a full power strip run. It is a little bit 'neater' than building a liebig big enough to handle full power, but it is a matter of personal choice.

When you do the condenser calculations for your available power input, if your liebig is going to be too long to be convenient, there are a lot of other condenser design options available.

[Bushman]

Sorry forgot to say that with that length of 2" tube you have plenty for a VM column and a pot still. You could use the same condenser on both, but I would reserve a bit of the 2" to make a pre-condenser. Wind yourself another coil to go inside the 2" tube and put it on the pot still just above your product condenser.

You will probably only need to use it when you are doing a strip run. If you build your condenser so it is the correct size to cope with a spirit run, then it might not have enough cooling capacity for a full power strip run. It is a little bit 'neater' than building a liebig big enough to handle full power, but it is a matter of personal choice.

When you do the condenser calculations for your available power input, if your liebig is going to be too long to be convenient, there are a lot of other condenser design options available.

This is a good point! I don't do stripping runs but I stripped a piece of copper wire and soldered it at a 30 degree angle winding it down my inner 1/2" coil of my liebig between the area where the water enters at the bottom to where it leaves at the top to create more turbulance, but would think for stripping runs you would want something a bit bigger!

[Stillbilly]

Sorry forgot to say that with that length of 2" tube you have plenty for a VM column and a pot still. You could use the same condenser on both, but I would reserve a bit of the 2" to make a pre-condenser. Wind yourself another coil to go inside the 2" tube and put it on the pot still just above your product condenser.

You will probably only need to use it when you are doing a strip run. If you build your condenser so it is the correct size to cope with a spirit run, then it might not have enough cooling capacity for a full power strip run. It is a little bit 'neater' than building a liebig big enough to handle full power, but it is a matter of personal choice.

When you do the condenser calculations for your available power input, if your liebig is going to be too long to be convenient, there are a lot of other condenser design options available.

Thanks for the info Myles!
I have 10' of 2" pipe so plenty to spare. I thought most pot/whiskey stills just had product condensers. (i could put my 1/2" x 40" 102cm liebig on it, which should knock it all down (?) ) Does a pre condenser above take off slow your stripping runs much? I will have to read more on this. Running it on LP gas.
My current single coil column condenser is 13" (33cm) long using 1/4" .6cm OD which I plan to pack some copper mesh into.

Regarding column packing, have you used this type of packing material? I'm looking for the best way to roll/stuff it in there (ok.. I will be HD searching as well
copper mesh is in a tube construction, 5"/13cm wide. Have 3 lbs of it. TY!

[Stillbilly]

Ok, I found some pre-condenser pics and yes that is a good Idea to use with stripping. Pre-condenser on the top of the liebig.. not the column. I will likely build a separate whiskey still after VM is whistling Dixie.

[Stillbilly]

(from library.thinkquest.org)

turbulence.gif (9.45 KiB) Viewed 1457 times

Regarding turbulence, I was thinking of using a washer but it would not be easy to adjust up and down and I also question the amount of turbulence it would generate.
I'm going to install a 7/8" o.d. copper pipe inside the 2" column below the take off T. It is adjustable vertically being a tight fit with no solder so tweaking will be easy.
I am drilling a hole in the center of it and will solder or tight fit a short copper 12 gauge wire to help any condensate to pool and drop back off into the center of the packing.
I don't think I'm inventing any new wheel here but if you have some insight, good or bad let me know.
I'm planning on sliding it down the column, 3" below take off and have packing 3" below this.

I think the tube's placement will be dependent upon the vapors velocity and viscosity that hits it, among other things.