VM spirit run, neutral

[casper the Irish]

Hey, one of my crazy ideas finally gets put to the real world test. As all ideas should be. Thank you, casper.

The basic point of this design idea was to see if it would help lower the minimum reflux ratio (for a given column : takeoff port




4. keep the horizontal section as short as practically possible (without being obsessive about it), and keep the reflux port nearer the output end (i.e. after the vapour has finished the 90º turn to horizontal),

Keeping both ports tighter together, do I still want them close to the bend. Is that to get vapors into the RC quicker. Just asking since seeing those pics of horizontal RCs makes me wonder bout what my wee length of 2" is actually doing. Seems needed by the splitter tee design but happy to remove


5. easy enough to add LM, either by inserting a small dam near the column end of the horizontal section, or setting up the reflux condenser shell as a liquid trap, like some of Bokakob's designs (and I have done a drawing or two showing how to do that with this design idea)

I will insert a bypass; I did do the boka option on the RC shell as you drew so all condensate should now return direct below the ell.

6. make sure the reflux is returned to near the centre of the packing (at the top).

I have an upturned 10mm pipe in there. It reaches a few inches up into the bend

Looking forward to hearing how it all works.

Cheers

[casper the Irish]

Amended as recommended.

Return condensate to column

Needle valve

This neat wee needle valve costs less than 10 dollars and accepted push fit copper or nylon. And releases it.

With separation of condensate as devised by Harry.

Harry's bypass

RC

Shorter lyne arm
Closer and horizontal valve, optional fit
Full Condenser return to top of packing
Turbulation on top of packing
Dry (cleaner?) outflow
Sharper Heads extraction

[skow69]

Way to go, Casper! I am highly impressed. Let us know how she runs. I'd bet real money that the improvement will knock your socks off.

Cool needle valve. Those 2 wires are not going into it, right?

2 comments.

1 If it was me, I would snuggle the LM valve up as close as possible to the tee. just to avoid any extra smearing. I can't tell where your valve is from the pics, but the volume of liquid that is capable of stirring up your fractions and ends up lost is everything from the valve up to the level of the tube opening inside the column.

2 This is what thepatchworkdoll was referring to. In potstill mode, if the cap that replaces your reflux coil was sealed on tight and the VM valve was shut it would blow your roof into the next county. Harry and Pint-o-shine beat me up good over that. It's worth doing whatever you need to to make sure it can't happen.

Good work. Have fun. Make booze. Don't forget the cleaning runs.
skow out.

[casper the Irish]

Thanks Skow



Wires were in the background, lighting for the woodfired oven. The loose cap is for the stripping runs I now can do with valve removed

I did change that tee to lower the valve just so I could reach it better. It's a 1/4" (8mm) branch on 3/8?(10mm) so figured a few teaspoons pooling won't matter. When opened won't there be a siphon draw to the spout no matter where the valve is? Needs care not to suck vapor when discarding those teaspoons.
. But I will put it back where it should be. A cool loop like yours or s-trap after the tee could do it, but I also want to keep it tidy looking and handling since it comes apart for safe keeping.



And thanks for reminding me about cleaning run, I'm so mucky thinking lead free don't need to bother, forgot the flux

[HookLine]

Hey, one of my crazy ideas finally gets put to the real world test. As all ideas should be. Thank you, casper.
.
.
.
Cheers

'bout time you showed up.

I been away pirating.

I come back to port, and I see you lot have been breeding like mad. Nearly 26000 of you now.

[HookLine]

Looking good, casper, apart from shifting the LM valve closer to the tee (but still slightly below it).

Then run her up and see how it goes.

[HookLine]

The minimum reflux ratio you can achieve on a VM is determined by the cross sectional areas of the two vapour paths when the VM valve is wide open.

skow69 covered it. But my 2c worth...

You are right, given the vapour pressure at both ports is equal. But that doesn't apply so neatly when the vapour has momentum in favour of one of the ports – i.e straight at one of them, and going past the other like a venturi effect. How much difference it makes in this situation I don't know, but that is what experiment is for.

Of course, just using a bigger VM take-off port and valve would definitely reduce minimum reflux ratio.

[casper the Irish]

A daftie question. Not sure I understand the double negative " reducing minimum ...ratio" . Do I want less reflux?

[HookLine]

Possibly.

Limitation of standard VM design is it has a fixed minimum reflux ratio with the take-off valve wide open, determined by the port ratios, but rarely below 1:1, so not so good for pot stilling.

But if you can lower that minimum ratio substantially below 1:1, so there is much more vapour going down the take-off path than to the reflux condenser, you can get into pot stilling territory, for a spirit run not stripping runs. (Pot stills often have a bit of passive reflux going on in risers and lyne arms.)

Another trick is to restrict the vapour path above the take-off port into the reflux condenser section, so it is smaller than the take-off port or valve, which gets you below 1:1.

But make sure it doesn't choke. If the reflux is being dropped straight back down the column then the restriction can't be smaller than half the column diameter. If the reflux is being returned via a different pathway, like in yours, then can get away with a third of column diameter.

[casper the Irish]

You have turned the lights on for me, thanks Hookline so much.
Valve snug as recommended, how "slightly lower"?. 10mm pipe turns upward inside. Valve 8mm, hope its enough.

Snug valve

Your design asks for unequal ports, RC 1" outtake 3/4" (on 2" column). I could put a restrictor inside the RC shell where as you suggested I have a boka trap with loose fitting tee (1" equal). I could fit a 1/2" tee instead which I reckon equates to slightly less than 3/4" -just under your limits of 1/3 column dia. With the Venturi it will make an interesting variable to test. Thanks again, setting me free to explore

[HookLine]

You have turned the lights on for me, thanks Hookline so much.
Valve snug as recommended, how "slightly lower"?. 10mm pipe turns upward inside. Valve 8mm, hope its enough.

Angle the tee slightly downwards, with the valve slightly below the tee so the liquid goes to the valve first, not down the reflux return line into the column. Guarantees full control of the liquid flow. Something like this:

Thanks again, setting me free to explore

Only important rule for exploring and experimenting with stills is to do it safely.

[casper the Irish]

Is that not dealt with by the internal up-bend as in Harry's sketch. Return Pipe opens 3" above the tee and valve.

It will take me a week to gather wines for next run.... But have been reading Dad300 on ethyl carbamate. Several research papers show high levels of this stuff in reflux columns and molasses runs Dad interprets the findings to conclude (and I agree) that although copper packing is good to clean vapours on the way up, there is a problem when copper is washed with liquid condensate both in reflux and on the way down thru cooling to collection. This is made much worse by the practice I follow of recycling feints, dunder/backset and trub.

So before I can run again...
New SS leibig required.
Can't redo the bypass in SS but I wonder if dense packed SS scrubbers will work above the valve and around to outtake?
No more pot ale nor trub. Sad loss of flavours.

[casper the Irish]

I made the changes and ran rum low wines 28% thru the 2" copper reflux column amended.

Observations In no particular order:

Take off up 2% at 91%abv with 3/4" valve fully open. About 1.5KW
I do not yet have skills finessed and assume this can be improved by practice?

I set the gas ring about 80% below column flooding (choking). Harrys bypass at 10mm is Still full to choking, possibly throwing condensate into the lyne arm. Reducing heater to 50%. Bypass needs to be 1/2"?

I capped the boka with sawn pipe clipped over the 1" port, restricts RC opening below 1" Does this reduce abv as well as rr?

I am happy with 91% when stilling rum or grain. In fact it may be ideal. I don't think its good enough for vodka nor gin.

How do I do that? Will try slowing it down, increasing rr by restricting outflow a bit....

New packing installed, SS soft mesh, about 3m of 8" widths rolled tight-ish. Column insulated with Silver bubble wrap foil.

Run of 50 l low wines molasses at 28% I got 8l 91% falling to 89% before I stopped.
Two things.
How is it possible to go deep into tails on a VM ( for those golden rum oils) if the abv stays high?
At this point the temp jumped from a steady 78°C by a few degrees and the smell/ taste changed dramatically. Strong aromatic tasted like detergent. Bitter sweet overpowering almost fragrant like washing powder

[casper the Irish]

The minimum reflux ratio you can achieve on a VM is determined by the cross sectional areas of the two vapour paths when the VM valve is wide open.

skow69 covered it. But my 2c worth...

You are right, given the vapour pressure at both ports is equal. But that doesn't apply so neatly when the vapour has momentum in favour of one of the ports – i.e straight at one of them, and going past the other like a venturi effect. How much difference it makes in this situation I don't know, but that is what experiment is for.

Of course, just using a bigger VM take-off port and valve would definitely reduce minimum reflux ratio.

This opens my thinking to Dads two modifications of the CM innovation by Manu de Hanoi

CCVM An open equal Tee to outport and cc
CCVM /LM branch head "Y"

Mechanically set at 1:1 but in practice, can be operated as VM,mLM and potstill