Building a world class stripper ...

[DAD300]

If the cooling coil is slightly loose, you can add some Scrubbie around it as a barrier.

Also the coils don't have to be perfectly uniform. Make one or two coils in the middle press fit to the out side dia. I taper my coils on purpose.It exposes more coil surface to the vapor path.

You thought I was just making sloppy coils?

As to reflux missing the collection funnel-
1. the condensate will flow down the coil to a great extent.
2. I'm not sure why we are condensing inside the column of a stripper.

[Grey_Meadow]

2. I'm not sure why we are condensing inside the column of a stripper.

See Odin's opening post. The idea is to put everything in a single column with no / few bends or constrictions. The funnel idea is Odin / Windy from a previous face to face discussion. Odin opened this thread to get new / other ideas. The desire to take off 100% of the condensate and therefore 0% reflux into the boiler.

I have another iteration in mind that I will get on paper this evening.

[Odin]

Yes, I found that if you use less material in your still, do not block / bend gasses as much as you can, you can get off wordly stripping results. Think 80 liters per hour on a 5 inch diameter design like the design that is being adapted here. Not saying one should go to 80 liters per hour, but the same rules of design may apply to a hobby size still.

Odin.

[Jacksonbrown]

Don't block the gasses?!? Is that in reference to DADs tapered comment?
You want them the hit the condenser, don't you???

I can't see the benefits that head design with the funnel has over a simple two slant plate design.
A boka head would be much easier to fabricate and is able to easily divert 100% of the distillate away.
I agree that with the weir empty you will have an open path for vapour to escape, you will need a trap.

[Lester]

When gases are allowed to expand they cool down. When gases are compressed they heat up.

This is a fundamental concept to consider in addition to gas flow and intimate contact with the condenser. I had deliberately made my condenser housing bigger so there will be a sudden pressure drop (interpret as additional cooling) once the gases are out of the riser.

[Grey_Meadow]

Attached are two more concepts.
New comers to this thread, please read the first several post to understand the objective of this thread, please stay on topic.
The idea here is a World Class Stripper.
1) Single Column with minimal obstructions to the vapor flow up.
2) 100% recovery of the Reflux.
Please don't deviate from these two requirements.

Some of the sketches are mind ideas, most are not. I am just the instrument to put ideas into picture.
Comment but don't criticize. I have added Labels to these two concepts to help with the discussion. I will back edit the other sketches with labels

Concept E uses a vertical arrangement of corrugated tubing that is "wrapped 4 times" (IN down, up, down ,up OUT). The recovery system is a central funnel.

Concept F uses the more typical spiral wrap and the traditional Boka Slanted plate recovery one on each side to recover 100% of the reflux.

Single_Column_Stripper.pdf

(42.15 KiB) Downloaded 151 times

[Jacksonbrown]

Why do you need negligible additional cooling when you have a coil?

In an alembic you have a slight restriction coming out of the boiler to induce a bit of reflux in the riser which comes out like dew (the effect you’re referring too I believe). I guess this bumps up the ABV and increases separation a small amount.

In any case, having the pressure drop after the product take off in a stripper still doesn’t make a lot of sense to me as the coil is doing all the cooling work for you and reflux in the column is not likely.

I’ve got a pretty good understanding of fluid mechanics and thermodynamics. I think you’ll find the pressure drop will be minimal in a system that is open to atmosphere.
It would be negligible IMHO unless you had very high vapour velocities. The pressure drop you talking about is in effect an orifice plate.

http://en.wikipedia.org/wiki/Orifice_plate

I don't enjoy math as much as some but it can all be calculated if your that way inclined.

In addition the vapour that cools will condense on the coil, dropping in volume dramatically. The void will simply be filled with more vapour.
The pressure at the top of the column will be balanced with that at the vent.

[Windy City]

Thanks Grey meadow and Dad
Grey meadow that drawing is exactly what I was thinking, including the 4"at the condenser protruding down a little so as to direct the condensate to the funnel and not run down the walls. Thank you for the drawing I kind of gave up the idea pretty quick of keeping the condenser 6" because I couldn't think of a way to channel the condensate into the 4" funnel and I really don't see a need for the condenser to be 6". The 6" section is only there to accommodate the space taken up by the 4" funnel and not have a choke point that increases velocity.
Thank You everyone for the input and help, my flute has been taken me forever to build but I have all these parts in the shop and shouldn't take me very long to burn up.

Again Thanks
Windy City

[Jacksonbrown]

Concept F uses the more typical spiral wrap and the traditional Boka Slanted plate recovery one on each side to recover 100% of the reflux.

Rather than two weirs and take offs just slant the top plate down (so the two are parallel) to divert flow to the bottom weir.
So long as there is vertical overlap you will still recover 100% of the distillate through the one take off.
This is how my LM head is anyway. It easily allows for 0% to 100% reflux depending on valve position.
Reflux isn't so relevant in this operation but it is still a simpler design.

[Lester]

From the preceding discussions.........

........if a person has a VM or LM still and he removes the reflux column and replaces it with a very short tube to connect the boiler to the reflux condenser........it has now suddenly become a "World Class Stripper".

[Odin]

Hi there, nice to see the plans progressing. Beautiful pictures, Grey! You do that for a living? Drawing and stuff?

I'd advice against the slanted plates, given they cause a lot of splatter. Part of that splatter will fly around, disrupt gass stream and - just in itsself - will fly over the plate, back down into the column. No problem in a normal Boka, but as a stripper, with higher gass speeds and more reflux, it will make you loose some efficiency.

I like concept E, but the cup an cooler seem to be very close. I suggest some testing prior to assembly, to make sure the relative small size cup does actually collect all the reflux. The other thing is that a little bit more of space (vertically) may be needed between cooling spiral and the cup. This is why (and again, some prior to assembly testing will show if it needs that): liquids will fall from the cooling tube in pretty massive amounts.If they are very close, the funnel and the tube, reflux may not just be falling but also being trapped in between tube and collection vessel, creating a sorta "bridge", where the reflux transfers more cooling to the collection cup than needed. The reflux is supercooled and will already cool the cup. The inside and the outside. The outside of the cup, if it gets cooler, will create some unwanted passive reflux. If the cooler and cup touch (e.g. via liquid not just falling, but bridging the space between them), more than needed passive reflux on the outside of the collection cup may form.

I think a slight down angle on the tube out is good, as Windy suggests. I also feel no liquid trap should be in place, because that will create hold-up. And you want to syphon out the liquids as soon as you can.

Posting while Lester was.

Odin.

[Odin]

From the preceding discussions.........

........if a person has a VM or LM still and he removes the reflux column and replaces it with a very short tube to connect the boiler to the reflux condenser........it has now suddenly become a "World Class Stripper".

Hi Lester, it won't work on a VM outlet, because abv of stripper gasses is too low. Also: with a VM you will need the column cooler as well as a product cooler. More material means less efficiency in terms of gross power input translating into maximum amounts of collectable & warm reflux.

But your summary is a great one!

Odin.

[badbird]

If reducing back pressure is the issue maybe something like this might work.

The condensing/collapsing vapor should pull more vapor from the riser to the surrounding condenser coil quite efficiently. The condenser chamber would probably have to be quite a bit taller but you get the idea.

[badbird]

Actually after thinking about it a bit more the chamber should be shaped to have minimal contact with the raiser to reduce passive reflux. Like this,

[Jacksonbrown]

I like the other one BB, I guess that’s what Lesters is like on the inside but still think your not going to capture 100% with either.
I would use a double coil RC that slips in between the inner and outer tubes and bring the baffle right down (A SS scrub in there would lose distillate down the center).
With 0% reflux you will still need a vapour trap. A simple S bend in some silicon tubing would do the trick.


The biggest problem with the funnel is you are constricting the vapour path up but not getting 100% of the liquid coming down the walls which are air cooled. What are the drips doing with the funnel design?

The two plates working together cover 100% of the column cross section but individually only block 55% of the vapour path (assuming 10% overlap).

Everything running down the walls is diverted and collected and any drips hitting the angled plate are actually directed towards the outlet.

What is the big issue with a simple pot???
That’s effectively what I use with an uninsulated copper packed column to drop a bit of water. It works fine and collects 100% of what hits the still head with no mucking around.
It also allows for proper cross flow in the condenser which means higher efficiency, less water usage and as a bonus the distillate comes out cold.
The only real improvements I see is to do away with the boiler and thus start up times and also add heat recovery.

Considering no cuts are to be made the simple answer to World Class to me is continuous but the rules you guys are playing by seem a little vague.

[DAD300]

The funnel on top of the column and below the coil will speed the vapor as it has to compress and go around the funnel. The funnel becomes a restriction to the column dia.

[badbird]

JB, A double condenser coil around the inside wall of the condenser chamber no doubt increase efficiency and the only reason its not on the diagram is that was harder to draw
I'm not sure that that kind of condenser efficiency will matter that much in a commercial situation where you are recirculating your coolant through a heat exchanger of some kind and not wasting tap water. Provided you are able to knock down all the vapor of course.
I am sure that Odin has plenty of experience with the use of slant plates and has his reasons (including back pressure) for not wanting to go that way. I have always used CM of one kind or the other so have no first hand experience with them.

The baffle / deflector cone probably should be sharper and go further down into the chamber and if it is stainless and well insulated there shouldn't be much vapor condensing on it and dripping down the raiser to the boiler

Not sure about the air lock on the distillate tube but i guess if it was large enough and there was a problem the over pressure would clear the tube quickly enough and allow venting.

On the subject of continuous stripping I'm starting to think fro my limited experiments that its fine for Vodkas etc but on things like rums and whiskeys apart from solids plugging things up, the hour or so being boiled up in the pot can make some significant changes to flavor but its all a bit difficult to quantify. The large commercial distillers that use continuous strip must have ways around it.

Anyway its Odins party so we play by his rules

[googe]

That second pic is great Badbird

[badbird]

Thanks Googe, Just need to find some suitable copper behind the shed and build it. Never know, it might even work!

[googe]

only one way to find out I'm really interested in all this but can't follow the numbers you all talk .only thing along these lines I've tried is, I had the boiler with a few hundred ml of water in it, heated it hot, had a feed tube at the base of my pot still, had a fermenter connected to the feed, had the feed from.the fermenter at a slow stream, trickle, it was kind of flash heating when it went into the boiler, the output didn't change but the ABV was all over the place. I had a thread about it but I've searched everywhere and can't find it!!!. I wrote down a detailed run of it.

[badbird]

I think I have seen that thread of yours somewhere or maybe just mention of it. The flash striping idea has potential but not sure how the solids from the wash would be dealt with. Lately I have just been stripping using my 50l boiler as steam generator, mounting 4 bubble cap plates above it and feeding wash at the top plate. If you don't push it to the limit its as stable as a rock. This condenser would look really mounted at the top

[Maritimer]

Now to get rid of the column completely.

On the base is the continuous stripper outlined previously. As for getting sufficient time to get the flavours from the mash, that can be set by the volume of the first quadrant. The following three need to be small in order to make significant deletions in the ethanol content.

There is more than enough heat to preheat the mash, so a second condenser is required.

The large-diameter worm contains the mash. It can be fed by gravity using the valve system outlined before, or a peristaltic pump could be used in a cost-insensitive system.

If a peristaltic pump were used, the mash would be fed into the bottom of the worm.

Notice that the bottom of the condensers is open to atmosphere. If any vapour comes out, this would have been an overpressure in a closed system.

M

[Lester]

Lately I have just been stripping using my 50l boiler as steam generator, mounting 4 bubble cap plates above it and feeding wash at the top plate.

Would be nice to see some pics of your setup.

[badbird]

Would be nice to see some pics of your setup.

This is working OK for what is needed here but could do with a few more plates to increase the efficiency. 4 sight glasses where installed after those photos where taken so now the top sight glass can be replaced with a blank plate with the wash injection point. Spent wash is diverted to waste before entering the boiler so its clean steam doing the striping.

Anyway it not pretty but it makes good use of what is already to hand here.

diverter1.jpg (11.84 KiB) Viewed 2662 times

[Lester]

That's gorgeous Badbird!!!

[badbird]

Thanks Guys, Just every time I see those photos reminds me I need to find that center easy flange and redo it, the one with the leak and that makes the column look crooked .