Liebig, twisted wire or no?

[squigglefunk]

I have a 5ft liebig 3/4" over 1/2" I soldered and twisted a thin wire along the length between the outside of the 1/2" and the inside of the 3/4" as some people showed in their builds on this site.I thought I have also read about a twisted wire up inside the 1/2" pipe? I have tried both ways, at first I didn't use it and the condenser seemed to work fine, but I was doing my last cleaning run and as the still first started I did see some vapor coming out as the first dribbles started. I then added a thicker solid copper wire twisted as best I could up inside the length of the vapor tube. It seems like it does help, I seemed to be able to turn the water flow down even more and seemed to get a better (longer?) temperature gradient down the condenser. I will be running the condenser in a mostly vertical position so I don't think the wire will cause too much extra pooling/smearing of condensate, but I would think if run more horizontally this could be an issue... any other thoughts on the twisted wire techniques? thanks

[higgins]

My liebig is 28" of 3/4 over 1/2.
Stripping 12 gallons of wash in my 15 gal kettle with 5500w element I could only run at about 30-32% power before I'd get vapor coming out.
I recently took it apart and added a spiral of copper wire between the pipes.
Now I can run at 55-60%, which makes stripping runs go a lot faster now.
Shows that adding that wire made the liebig nearly twice as efficient.

[squigglefunk]

thanks, great real world data, much appreciated

[zed255]

I built a 36" (from water inlet to water outlet, overall length is a little longer) long 3/4" over 1/2" and opted to use the spiral between the vapour tube and jacket, 12ga solid copper wire. I have to actually reduce my water pressure to 10-12 psi using an RV type adjustable pressure regulator to get water flowing slowly enough through a cheap 'needle' valve to even get a gradient at all. It knocks down my full 6kW during an alcohol run, I have to back off as proof drops but it can still handle about 4.5kW down to essentially water.

I can get some huffing at lower proof output but at no time does actual vapour escape. Never bothered me enough to experiment with trying to solve it. I could envision a wire in good contact with the vapour tube providing more cooling surface area, some added turbulence and increasing dwell time of both vapour and condensate. I operate my Liebig closer to horizontal rather than vertical, as such I've not tried it. The shallower angle seems to work well for me.

[psf]

I built my Liebig 48” 1” over 3/4 with a solid 12 ga copper wire twisted and soldier in place along the outside of the 3/4. I run it at 45 degrees and it knocks down 4500W wide open on a stripping run with no huffing.

I was at one point, balling up some copper mesh and putting it in the elbow at the top of the Liebig to cause turbulence in the vapor path. Realized I didn’t need it.

I would think that your 5’ would knock down a lot. If it’s not it maybe your angle or you may need some disturbance in the vapor path.

[Truckinbutch]

I've posted about my Liebig with wire in coolant and in vapor path . Would have it no other way . Knocks down whatever I throw at it .

[NZChris]

I posted about my water jacket experiment here;

viewtopic.php?f=87&t=57690

[bluc]

I did a crimped 1" over 3/4" didnt crack a sweat on 3600w. Could hold my hand on it half way along easy..

[squigglefunk]

the link NZChris provided did give me a nugget of info

"4) Vapour path turbulators at the cold end e.g. scrubbies. I have not measured the effect of these. But it seems likely that they will slow the distillate flow and so give it more time to cool. They also catch the mist that is created in a Leibig, which is better than losing it. (This mist is cool and does not burn, as opposed to true vapour that is hot and very aggressive.) Lots of people swear by vapour path scrubbies, so this is probably right."

I think this "mist" might have been what I was seeing coming out of my liebig as it started to produce? There was cool liquid coming out as well as a slight vapor but it did not seem "hot" ... I have never seen it before and don't ever remember reading about it...

I would suggest the twisted thick wire I shoved up inside my vapor tube is possibly helping with the "mist"

[TwoSheds]

I've seen the mist at startup and during a run with both my commercial and my Twisted Brick shotgun. Tried, but failed to get a picture of it.

I believe it to be alcohol vapor which has condensed mid-air rather than on the walls of the condenser. It seems to only happen when the condenser is very cold, either at startup or because I have too much cooling water going through it which would make sense. Also it seems to be worse when the condenser is vertical.

On the fly, i try to tune down the condenser water flow and that seems to fix it. I suspect something to interrupt (but NOT slow down) the vapor flow would do the same thing.

Remember, any time you constrict the path for a fluid (remembering gas is a fluid) it will flow faster, not slower, but it will provide turbulence. After it clears the restriction it will slow down which may have its advantages, but my guess is it's more likely the turbulence or increased surface area of anything you stick up there that will pull the mist out of suspension.

Just be careful any time you're interrupting the vapor flow not to BLOCK it!

TwoSheds

[jonnys_spirit]

The mist is real. It's not vapor. You can see it really very well when you silhouette the business end of your PC with back lighting and look at it just so...

Cheers!
-j

[TwoSheds]

The mist is real. It's not vapor. You can see it really very well when you silhouette the business end of your PC with back lighting and look at it just so...

Cheers!
-j

You're right Jonnys, vapor is the wrong term. "Vapor" implies it is still in a gaseous form. "Mist" is a better term.

I'll have to get more creative with lighting next time I try to get a pic.

[subbrew]

I can get some huffing at lower proof output but at no time does actual vapour escape. Never bothered me enough to experiment with trying to solve it. I could envision a wire in good contact with the vapour tube providing more cooling surface area, some added turbulence and increasing dwell time of both vapour and condensate. I operate my Liebig closer to horizontal rather than vertical, as such I've not tried it. The shallower angle seems to work well for me.

Not to pick on anyone, but I have seen this multiple times and need to correct it. Adding a scrubby or wire will not increase dwell time. Dwell time is totally related to to amount of vapor produced (power in) vs volume of the output pipe. If adding something to the pipe slowed down the vapor, it would build up and increase pressure until the speed increased back the equilibrium state.

It increases surface area, so with good conduction to the cooling water will actually condense the vapor sooner, decreasing vapor dwell time. And it can also increase turbulence which decreases laminar flow giving better heat transfer.

[zed255]

Perhaps I misused dwell time, but most of what I said I stand by. The wire increases surface area, increases turbulence and will promote prolonged contact of condensate, thereby producing cooler product. The liquid phase will enjoy a longer dwell time but not necessarily the vapour. The vapour will simply condense in a shorter distance, as you said.

The direct quote does call me out specifically, so you are in essence 'picking' on someone.

[jonnys_spirit]

When I run with the liebig I use some copper mesh entwined into a spiral copper wire the length of the leibig. A small bit of mesh towards the vapor end and a small bit of mesh towards the business end and I actively monitor for any indication of blockage (eg; product output stops or slows unexpectedly) and can (and do) remove the whole thing at times to compare... I don't have mesh the whole length of the 48" liebig. Maybe 3-4" on each end.. Sometimes I run with or without it too!

Cheers!
-j

[still_stirrin]

Not to pick on anyone, but I have seen this multiple times and need to correct it. Adding a scrubby or wire will not increase dwell time.

Dwell time is totally related to to amount of vapor produced (power in) vs volume of the output pipe. If adding something to the pipe slowed down the vapor, it would build up and increase pressure until the speed increased back the equilibrium state. <— increasing boiler pressure would also increase the temperature needed to boil the mixture. So, you’d put MORE heat into the boiler to produce the same mass flow of vapor. This could potentially turn your boiler into a bomb!

It increases surface area, so with good conduction to the cooling water will actually condense the vapor sooner, decreasing vapor dwell time. And it can also increase turbulence which decreases laminar flow giving better heat transfer.

Excellent subbrew!

As a compressible fluids mechanical design engineer with natural gas production experience, I totally corroborate your note. Very well put. I’ve tried many times to express this physical phenomena but it often gets misconstrued in interpretation.

What you’ve written is “the truth”. Thanks.
ss

[Twisted Brick]

<— increasing boiler pressure would also increase the temperature needed to boil the mixture. So, you’d put MORE heat into the boiler to produce the same mass flow of vapor.

As a compressible fluids mechanical design engineer with natural gas production experience, I totally corroborate your note. Very well put. I’ve tried many times to express this physical phenomena but it often gets misconstrued in interpretation.

Great discussion, gentlemen. I've always wondered about the incremental value of liebig 'enhancement' considering copper's already outstanding heat transfer properties.

s_s, a few years ago you posted that inserting a copper wire spiral (shell side) can increase the Reynolds number (presumably as a result of increased turbulence). From my reading, significant Reynolds numbers require turbulence as a result of a change of fluid (coolant) speed and direction. Is this correct? Given that a liebig's coolant speed is constant, and that (unlike a shotgun baffle that redirects coolant flow direction) a copper spiral merely linearly 'rotates' the coolant around the vapor tube, is any turbulence created notable/measurable? Add in the fact that as a coolant heats up it expands, creating shell-side pressure, could this added pressure limit any turbulence potential?

My guess is that to have any significant effect, a copper wire spiral needs to be wrapped tighter (more spirals rather than fewer) and coolant flow very high.

[higgins]

TB,
I soldered a 12 gauge wire on the outside of the 1/2" inner tube at one end, then spiraled it tightly around the tube 5 or 6 times, then soldered the other end.

As I said earlier, before I topped out at 30-35% power on stripping runs ... any higher and I would get hot vapor. After the change I can run at 55-60% power. That is pretty significant in my book ... I can strip nearly twice as fast and I use less water.

[Truckinbutch]

TB,
I soldered a 12 gauge wire on the outside of the 1/2" inner tube at one end, then spiraled it tightly around the tube 5 or 6 times, then soldered the other end.

As I said earlier, before I topped out at 30-35% power on stripping runs ... any higher and I would get hot vapor. After the change I can run at 55-60% power. That is pretty significant in my book ... I can strip nearly twice as fast and I use less water.

And there ya go . It's the little things that count .

[shadylane]

(This mist is cool and does not burn, as opposed to true vapour that is hot and very aggressive.) Lots of people swear by vapour path scrubbies, so this is probably right."

I think this "mist" might have been what I was seeing coming out of my liebig as it started to produce? There was cool liquid coming out as well as a slight vapor but it did not seem "hot" ... I have never seen it before and don't ever remember reading about it...

The mist is caused by C02 that's been cooled by the liebig.
When the cold C02 hits moist air, the air drops below its due point and forms a mist.

On a side note.
I think scrubbies make a liebig less efficient.

[Bushman]

My liebig is 28" of 3/4 over 1/2.
Stripping 12 gallons of wash in my 15 gal kettle with 5500w element I could only run at about 30-32% power before I'd get vapor coming out.
I recently took it apart and added a spiral of copper wire between the pipes.
Now I can run at 55-60%, which makes stripping runs go a lot faster now.
Shows that adding that wire made the liebig nearly twice as efficient.

I added wire to my first Liebig and was told at the time int improved performance by creating a turbulence. I had no real data to confirm but it worked great. Your comparison gives us some real data.

[jonnys_spirit]

One things for sure - it’s easy enough to wrap a 1/2” tube with romex gnd wire and tack solder it then slide it into the 3/4” to finish it up. The path of least resistance will make a good majority of the water flow in a spiral thus elongating the coolant path and providing more opportunity for HX and slower flow. It’s not a perfectly sealed system though so depending on how many tack solders you make and how tight it fits - results vary..

Coiled wire inside the 1/2” vapor/liquid output path? I do it but whatever. Probably not that significant based on my empirical observations.

Cheers!
-j

[squigglefunk]

thanks for all the input people

[robe]

I made a 3/4 over 1/2 3 ft liebig condenser. 3 ft of 3/4 plus about 6 in of 1/2 sticking out each end. I used #12 wire with about 6 wraps on the 1/2 in tacked with solder as per instructions from this site. Thanks by the way.
I had a hard time fitting the 3/4 over the 1/2. The last 6 in had to use a box end wrench to beat it the rest of the way which distorted the end of the pipe. I just cut off a 1/2 in with my pipe cutter. So all in all not too bad. I think I would use #14 next time for ease of assembly. Don't know if this would effect the swirling of the coolant water too much but would still provide some turbulence I would think.
Anyway I plan to cut a strip of copper sheet about 3/8 wide and about 3 ft long, twist it to about one twist per inch and put it in the vapor path.
This is part of my new build starting with a new 50 l keg I will post a picture in the new build thread. Thanks to everyone for all the great info on this site.

[robe]

An update on my liebig. I found some 1/2 copper All-Round(the stuff with the holes in it used for strapping pipe) I twisted a 42 inch piece and put that in the vapor tube. Doing my final cleaning run it worked really well. No vapor or anything else other than the good stuff coming out. I probably wasn't pushing as hard as some do. Anyway I am looking forward to making something other than weed killer.